Systems and methods for manufacturing bulked continuous filament

ABSTRACT

A method for manufacturing pellets from polymer, comprising: (1) melting polymer flakes in a first section of a melt processing unit to create a first single stream of polymer melt; (2) separating the first single stream of polymer melt into multiple streams of polymer melt by means of a separation element; (3) passing the multiple streams through a multiple stream section of said melt processing unit and exposing the multiple streams to a pressure within the multiple stream section of the melt processing unit as the multiple streams pass through the multiple stream section; (4) recombining the multiple streams into at least one combined stream of polymer melt; and (5) cooling the polymer melt and forming said pellets from the at least one combined stream. The intrinsic viscosity of the at least one combined stream may be determined and, in response, the chamber pressure within the multiple stream section adjusted.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/816,409, filed Mar. 12, 2020, entitled “Systems and Methods ForManufacturing Bulked Continuous Filament”, which is a continuation ofU.S. patent application Ser. No. 16/557,076, filed Aug. 30, 2019, nowU.S. Pat. No. 11,179,868, issued Nov. 23, 2021, entitled “Systems andMethods For Manufacturing Bulked Continuous Filament”, which is adivisional of U.S. patent application Ser. No. 16/432,579, filed Jun. 5,2019, now U.S. Pat. No. 10,538,016, issued Jan. 21, 2020, entitled“Methods for Manufacturing Bulked Continuous Filament”, which is acontinuation-in-part of U.S. patent application Ser. No. 16/220,733,filed Dec. 14, 2018, now U.S. Pat. No. 10,532,495, issued Jan. 14, 2020,entitled “Methods for Manufacturing Bulked Continuous Filament fromRecycled PET”, which is a continuation-in-part of U.S. patentapplication Ser. No. 15/419,955, filed Jan. 30, 2017, now U.S. Pat. No.10,487,422, issued Nov. 26, 2019, entitled “Methods for ManufacturingBulked Continuous Filament from Colored Recycled PET”, which is acontinuation-in-part of U.S. patent application Ser. No. 15/396,143,filed Dec. 30, 2016, now U.S. Pat. No. 10,493,660, issued Dec. 3, 2019,entitled “Systems and Methods for Manufacturing Bulked ContinuousFilament”, which is a continuation of U.S. patent application Ser. No.13/892,713, filed May 13, 2013, now U.S. Pat. No. 9,550,338, issued Jan.24, 2017, entitled “Systems and Methods for Manufacturing BulkedContinuous Filament”, which is a divisional of U.S. patent applicationSer. No. 13/721,955, filed Dec. 20, 2012, now U.S. Pat. No. 8,597,553,issued Dec. 3, 2013, entitled “Systems and Methods for ManufacturingBulked Continuous Filament”, which claimed priority from U.S.Provisional Patent Application No. 61/654,016, filed May 31, 2012,entitled “Systems and Methods for Manufacturing Bulked ContinuousFiber,” all of which are hereby incorporated herein by reference intheir entirety.

BACKGROUND

Because pure virgin polyethylene terephthalate (PET) polymer is moreexpensive than recycled PET polymer, and because of the environmentalbenefits associated with using recycled polymer, it would be desirableto be able to produce bulked continuous carpet filament, and otheritems, from 100% recycled PET polymer (e.g., PET polymer frompost-consumer PET bottles).

SUMMARY

A method for manufacturing pellets from polymer, according to variousembodiments, comprises: (1) melting a plurality of polymer flakes in afirst section of a melt processing unit to create a first single streamof polymer melt; (2) separating the first single stream of polymer meltinto multiple streams of polymer melt by means of a separation element;(3) passing the multiple streams of polymer melt through a multiplestream section of the melt processing unit and into a receiving sectionof the melt processing unit, and exposing the multiple streams ofpolymer melt to a pressure within the multiple stream section of themelt processing unit as the multiple streams of polymer melt passthrough the multiple stream section of the melt processing unit, whereina chamber pressure is maintained within the multiple stream section ofthe melt processing unit as the multiple streams of polymer pass throughthe multiple stream section, wherein the receiving section of the meltprocessing unit recombines the multiple streams of polymer melt into atleast one combined stream of polymer melt; and (4) cooling the polymermelt and forming the pellets from the at least one combined stream ofpolymer melt. In various embodiments, the intrinsic viscosity of the atleast one combined stream is determined, and, in response to determiningthe intrinsic viscosity of the at least one combined stream of polymermelt, the chamber pressure within the multiple stream section of themelt processing unit is adjusted.

A system for manufacturing pellets from polymer, according to variousembodiments, comprises: (1) means for melting a plurality of polymerflakes to create a first stream of polymer melt; (2) means for routingthe first stream of polymer melt through a separation element togenerate multiple streams of polymer melt; (3) means for exposing themultiple streams of polymer melt to a pressure within a multiple streamsection of a melt processing unit; (4) means for reducing the pressureof the multiple stream section of the melt processing unit to a chamberpressure; (5) means for, while maintaining the pressure of the multiplestream section of the melt processing unit at the chamber pressure,allowing the multiple streams of polymer melt to pass through themultiple stream section of the melt processing unit into a receivingsection of the melt processing unit; (6) means for recombining themultiple streams of polymer melt into at least one stream of polymermelt at the receiving section of the melt processing unit; (7) means forcooling said at least one stream of polymer from the at least one streamof polymer melt; and (8) means for forming pellets from said at leastone stream of polymer. In various embodiments, the system furthercomprises an intrinsic viscosity management system configured todetermine an intrinsic viscosity of the at least one stream of polymermelt, and, in response to determining the intrinsic viscosity of the atleast one stream of polymer melt, adjust the pressure within themultiple stream section of the melt processing unit.

A system for manufacturing pellets from polymer, according to variousembodiments, comprises: (1) a first section of a melt processing unit,the first section being configured to melt polymer to create a firstsingle stream of polymer melt; (2) a separation element configured toreceive the first single stream of polymer melt and divide the firstsingle stream of polymer melt into multiple streams of polymer melt; (3)a multiple stream section of the melt processing unit configured to: (A)receive the multiple streams of polymer melt, (B) allow the multiplestreams of polymer melt to pass through the multiple stream section andinto a receiving section of the melt processing unit, and (C) expose themultiple streams of polymer melt to a pressure within the multiplestream section of the melt processing unit as the multiple streams ofpolymer melt pass through the multiple stream section of the meltprocessing unit; and (4) a pressure regulation system configured tomaintain the pressure within the multiple stream section of the meltprocessing unit at a chamber pressure as the multiple streams of polymerpass through the multiple stream section. In various embodiments, thereceiving section of the melt processing unit is configured to: (1)receive the multiple streams of polymer melt, (2) recombine the multiplestreams of polymer melt into at least one combined stream of polymermelt, and (3) convey the at least one combined stream of polymer melttoward means for cooling and forming said at least one combined streamof polymer melt into said pellets, wherein the system further comprisesan intrinsic viscosity management system configured to determine anintrinsic viscosity of the at least one combined stream of polymer melt,and, in response to determining the intrinsic viscosity of the at leastone combined stream of polymer melt, instructing the pressure regulationsystem to adjust the chamber pressure within the multiple stream sectionof the melt processing unit.

Various embodiments are also described in the following listing ofconcepts:

-   1. A method for manufacturing pellets from polymer, the method    comprising:

melting a plurality of polymer flakes in a first section of a meltprocessing unit to create a first single stream of polymer melt;

separating the first single stream of polymer melt into multiple streamsof polymer melt by means of a separation element;

passing the multiple streams of polymer melt through a multiple streamsection of said melt processing unit and into a receiving section of themelt processing unit, and exposing the multiple streams of polymer meltto a pressure within the multiple stream section of the melt processingunit as the multiple streams of polymer melt pass through the multiplestream section of the melt processing unit, wherein a chamber pressureis maintained within the multiple stream section of the melt processingunit as the multiple streams of polymer pass through the multiple streamsection, wherein the receiving section of the melt processing unitrecombines the multiple streams of polymer melt into at least onecombined stream of polymer melt; and

cooling the polymer melt and forming said pellets from the at least onecombined stream of polymer melt;

wherein the intrinsic viscosity of the at least one combined stream isdetermined, and, in response to determining the intrinsic viscosity ofthe at least one combined stream of polymer melt, the chamber pressurewithin the multiple stream section of the melt processing unit isadjusted.

-   2. The method of Concept 1, wherein the method further comprises    crystallizing the plurality of polymer flakes, prior to melting the    plurality of polymer flakes in the melt processing unit.-   3. The method of Concept 1, wherein the multiple streams of polymer    melt fall into said receiving section of the melt processing unit    under the weight of gravity.-   4. The method of Concept 1, wherein the receiving section of the    melt processing unit comprises a particular extruder that recombines    recombine the multiple streams of polymer melt into the at least one    combined stream of polymer melt.-   5. The method of Concept 4, wherein the particular extruder is    disposed vertically below the separation element.-   6. The method of Concept 1, wherein the separation element is    adapted to divide the first single stream of polymer melt into at    least 8 streams of polymer melt.-   7. The method of Concept 1, wherein the separation element is an    extrusion die defining a plurality of holes, each of the holes    creating a respective one of the multiple streams of polymer melt.-   8. The method of Concept 1, wherein the first section of the melt    processing unit comprises a single screw extruder; and the receiving    section of the melt processing unit comprises a single screw    extruder.-   9. The method of Concept 1, wherein the plurality of polymer flakes    is derived, at least in part, from polyethylene terephthalate (PET)    flakes that are derived from recycled PET bottles.-   10. A system for manufacturing pellets from polymer, the system    comprising:

means for melting a plurality of polymer flakes to create a first streamof polymer melt;

means for routing the first stream of polymer melt through a separationelement to generate multiple streams of polymer melt;

means for exposing the multiple streams of polymer melt to a pressurewithin a multiple stream section of a melt processing unit;

means for reducing the pressure of the multiple stream section of themelt processing unit to a chamber pressure;

means for, while maintaining the pressure of the multiple stream sectionof the melt processing unit at the chamber pressure, allowing themultiple streams of polymer melt to pass through the multiple streamsection of the melt processing unit into a receiving section of the meltprocessing unit;

means for recombining the multiple streams of polymer melt into at leastone stream of polymer melt at the receiving section of the meltprocessing unit;

means for cooling said at least one stream of polymer from the at leastone stream of polymer melt; and

means for forming pellets from said at least one stream of polymer;

wherein the system further comprises an intrinsic viscosity managementsystem configured to determine an intrinsic viscosity of the at leastone stream of polymer melt, and, in response to determining theintrinsic viscosity of the at least one stream of polymer melt, adjustthe pressure within the multiple stream section of the melt processingunit.

-   11. The system of Concept 10, wherein allowing the multiple streams    of polymer melt to pass through the multiple stream section of the    melt processing unit into a receiving section of the melt processing    unit comprises allowing the multiple streams of polymer melt to fall    through the multiple stream section of the melt processing unit    under the weight of gravity.-   12. A system for manufacturing pellets from polymer, the system    comprising:

a first section of a melt processing unit, the first section beingconfigured to melt polymer to create a first single stream of polymermelt;

a separation element configured to receive the first single stream ofpolymer melt and divide the first single stream of polymer melt intomultiple streams of polymer melt;

a multiple stream section of the melt processing unit configured to:

-   -   receive the multiple streams of polymer melt,    -   allow the multiple streams of polymer melt to pass through the        multiple stream section and into a receiving section of the melt        processing unit, and    -   expose the multiple streams of polymer melt to a pressure within        the multiple stream section of the melt processing unit as the        multiple streams of polymer melt pass through the multiple        stream section of the melt processing unit; and

a pressure regulation system configured to maintain the pressure withinthe multiple stream section of the melt processing unit at a chamberpressure as the multiple streams of polymer pass through the multiplestream section, wherein:

the receiving section of the melt processing unit is configured to:

receive the multiple streams of polymer melt,

recombine the multiple streams of polymer melt into at least onecombined stream of polymer melt, and

convey the at least one combined stream of polymer melt toward means forcooling and forming said at least one combined stream of polymer meltinto said pellets, wherein the system further comprises an intrinsicviscosity management system configured to determine an intrinsicviscosity of the at least one combined stream of polymer melt, and, inresponse to determining the intrinsic viscosity of the at least onecombined stream of polymer melt, instructing the pressure regulationsystem to adjust the chamber pressure within the multiple stream sectionof the melt processing unit.

-   13. The system of Concept 12, wherein:

the first section is configured to melt a plurality of polymer flakes tocreate the first single stream of polymer melt;

the system further comprises a crystallizer configured to perform acrystallization step on the plurality of polymer flakes prior to meltingthe plurality of polymer flakes in the first section of the meltprocessing unit; and

the multiple stream section of the melt processing unit is configured toallow the multiple streams of polymer melt to fall into a receivingsection of the melt processing unit under the weight of gravity.

-   14. The system of Concept 12, wherein the receiving section of the    melt processing unit comprises a particular extruder that is adapted    to recombine the multiple streams of polymer melt into the at least    one combined stream of polymer melt.-   15. The system of Concept 14, wherein the particular extruder is    disposed vertically below the separation element.-   16. The system of Concept 12, wherein the separation element is    adapted to divide the first single stream of polymer melt into at    least 8 streams of polymer melt.-   17. The system of Concept 12, wherein the separation element is an    extrusion die defining a plurality of holes, each of the holes    creating a respective one of the multiple streams of polymer melt.-   18. The system of Concept 12, wherein the first section of the melt    processing unit comprises a single screw extruder; and the receiving    section of the melt processing unit comprises a single screw    extruder.-   19. The system of Concept 12, wherein:-   the first section of the melt processing unit is a first extrusion    means;-   the separation element is a polymer melt separation means;-   the multiple stream section of the melt processing unit is a second    extrusion means;-   the pressure regulation system is a pressure regulation means; and-   the receiving section of the melt processing unit is a third    extrusion means.

BRIEF DESCRIPTION OF THE DRAWINGS

Having described various embodiments in general terms, reference willnow be made to the accompanying drawings, which are not necessarilydrawn to scale, and wherein:

FIG. 1 depicts a process flow for a method of manufacturing polymerflakes according to an embodiment.

FIG. 2 depicts a process flow for a method of manufacturing bulkedcontinuous filament from polymer flakes according to an embodiment.

FIG. 3A is a block diagram of an exemplary system for manufacturingbulked continuous filament from polymer flakes according to anembodiment.

FIG. 3B is a block diagram depicting the operation of an exemplary meltprocessing system that may be used in a process for manufacturing bulkedcontinuous filament from polymer flakes according to an embodiment.

FIG. 4 depicts an exemplary polymer melt processing unit according to anembodiment.

FIG. 5 depicts an exemplary extruder that may be used in a BCFmanufacturing process according to an embodiment.

FIG. 6 depicts a cross-section of the exemplary extruder of FIG. 5.

FIG. 7 is a block diagram of another exemplary system for manufacturingbulked continuous filament from polymer flakes according to anembodiment.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

Various embodiments will now be described in greater detail. It shouldbe understood that the invention may be embodied in many different formsand should not be construed as limited to the embodiments set forthherein. Rather, these embodiments are provided so that this disclosurewill be thorough and complete, and will fully convey the scope of theinvention to those skilled in the art. Like numbers refer to likeelements throughout.

Overview

New processes and systems for making fiber from recycled polymer (e.g.,recycled PET polymer) are described below. In various embodiments, thesenew processes and systems may be more effective in removing contaminantsand/or water from recycled polymer than earlier processes. Variousdisclosed embodiments may also not require that polymer be melted andcooled as many times as required by current processes and systems. In atleast one embodiment, the improved processes and systems may result in arecycled PET polymer of high enough quality to be used in producingbulked continuous carpet filament from 100% recycled PET content (e.g.,100% from PET obtained from previously-used PET bottles). In at leastone embodiment, the improved processes and systems may result in arecycled PET polymer of high enough quality to be used in producingbulked continuous carpet filament from at least 50% recycled PETcontent. In particular embodiments, the recycled PET polymer may have anintrinsic viscosity of at least about 0.79 dL/g (e.g., of between about0.79 dL/g and about 1.00 dL/g).

Flake Preparation Process

A BCF (bulked continuous filament) manufacturing process, according to aparticular embodiment, may include performing one or more of thefollowing steps: (1) acquisition, sorting, and initial cleaning ofsource material comprising PET polymer (e.g., post-consumer polymerbottles, such as post-consumer PET bottles); (2) granulating orotherwise reducing the source material into flakes; (3) preparing (e.g.,cleaning and/or sorting) the flakes for use in the process; (4) passingthe prepared flakes through an extruder that melts the flakes andpurifies the resulting PET polymer; and (5) feeding the purified polymerinto one or more spinning machines that turn the polymer into filamentfor use in manufacturing carpets. These steps, and other aspects thatmay be integrated into various disclosed embodiments, are described ingreater detail below.

FIG. 1 illustrates a block diagram representing an exemplary Method 100for generating polymer flakes according to various embodiments. Invarious embodiments, flakes of PET polymer may be prepared frompost-consumer PET bottles. At Step 110, a system may acquire PET polymercontainers (e.g., bottles). The system may use, as a source material,bales of clear and/or mixed colored recycled post-consumer PETcontainers (e.g., bottles) that may have been obtained, for example,from various recycling facilities. Such containers may also, or instead,be acquired from one or more facilities accepting such containers asreturned ‘deposit’ bottles (e.g., PET bottles whose price includes adeposit that is returned to a customer when the customer returns thebottle after consuming the bottle's contents).

Such returned or recycled post-consumer containers may contain someamount of non-PET contaminants. Examples of such contaminants mayinclude non-PET polymeric contaminants (e.g., polyvinyl chloride (PVC),polylactide (PLA), polypropylene (PP), polyethylene (PE), polystyrene(PS), polyamide (PA), etc.), metal (e.g., ferrous metal, non-ferrousmetal), paper, cardboard, sand, glass and any other unwanted materialsthat may find their way into a collection of recycled post-consumercontainers.

The disclosed systems may be configured to utilize recycled PET (e.g.,as acquired at Step 110) of varying quality in the processes describedherein. For example, in various embodiments, the system may configuredto produce BCF from PET derived from PET bottles sourced from curbsiderecycling sources (e.g., PET bottles that were collected as part of ageneral bulk recycling program or other recycling source) as well asdeposit PET bottles (e.g., bottles returned as part of a depositprogram). In various embodiments, curbside recycled bottles may requiremore thorough processing in order to produce bulked continuous filament,as curbside recycled PET bottles may be mixed in with and otherwiseinclude contaminants such as, for example: other recyclable goods (e.g.,paper, other plastics, etc.), garbage, and other non-PET bottle itemsdue to imperfect sorting of recycled goods or for any other reason.Deposit PET bottles may include PET bottles with fewer unwantedcontaminants due in part because deposit PET bottles may be collectedseparately from other recyclable or disposable goods.

In various embodiments, curbside recycled PET bottles acquired duringparticular times of year may include more impurities and othercontaminants than at other times of the year. For example, curbsiderecycled PET bottles collected during summer months may comprise ahigher percentage of clear PET bottles (e.g., water bottles) at least inpart due to additional water consumption during summer months.

At Step 120, the system may remove non-PET contaminants from the desiredPET components (e.g. or recycled post-consumer containers). Inparticular embodiments, the system may remove smaller components anddebris (e.g., components and debris greater than 2 inches in size) fromwhole bottles via a rotating trammel. In particular embodiments, thesystem may sort the containers at Step 120 by performing a binarysegregation of clear containers from colored containers using automatedcolor sorting equipment equipped with a camera detection system (e.g., aMultisort ES machine from National Recovery Technologies of Nashville,Tenn.). In various embodiments, the system may use manual sorters atvarious points on a production line to remove contaminants, for example,those contaminants not removed using a rotating trammel and/or one ormore other methods. The system may also use manual sorters to separatecolored and clear containers that have not been separated by automatedsorting equipment.

At Step 130, the system may granulate the PET polymer containers (e.g.,using a 50B Granulator machine from Cumberland Engineering Corporationof New Berlin, Wis.) to render, grind, shred, and/or otherwise sizereduce the PET polymer containers into particles of a smaller size. Inan embodiment, the system may grind or shred the PET polymer containersinto flakes of, for example, a size of less than one half of an inch.These flakes, before undergoing a washing process, may be referred to as“dirty flake.”

At Step 140, the system may wash and sort the dirty flake. In variousembodiments, the system may remove contaminants such as bottle labelsand other undesired components that were not removed in the PET polymercontainer cleaning and sorting steps from the dirty flake via an airseparation system. Next, the system may wash the dirty flake to furtherremove any contaminants. The system may further process the washedflakes at Step 140 by identifying and removing any remaining impuritiesand/or impure flakes from the washed flakes. The system may use one ormore metal removal magnets and/or one or more eddy current systemsduring the execution of Step 140 to remove any metal contaminants. Inaddition, or instead, at Step 140 the system may use near infra-redoptical sorting equipment (e.g., an NRT Multi Sort IR machine from BulkHandling Systems Company of Eugene, Oreg., or a Spyder IR machine fromNational Recovery Technologies of Nashville, Tenn.) to remove loosepolymeric contaminants that may be mixed in with the PET polymer flakes(e.g., PVC, PLA, PP, PE, PS, PA, etc.). Additionally, or instead, thesystem may use automated X-ray sorting equipment such as a VINYLCYCLEmachine from National Recovery Technologies of Nashville, Tenn. toremove remaining PVC contaminants.

To describe the washing process of Step 140 in more detail, the systemmay mix the dirty flake into a series of wash tanks. As part of the washprocess, the system may use aqueous density separation to separate anybottle caps (e.g., olefin bottle caps, which may, for example, bepresent in the dirty flake as remnants from recycled PET polymerbottles) from the higher specific gravity PET polymer flakes. The systemmay wash the flakes in a heated caustic bath. In various embodiments,the system may heat the heated caustic bath to about 190 degreesFahrenheit. In various embodiments, the system may maintain the causticbath at a concentration of between about 0.6% and about 1.2% sodiumhydroxide. In various embodiments, the system may use soap surfactantsand/or defoaming agents that may be added to the caustic bath, forexample, to further increase the separation and cleaning of the flakes.Further, at Step 140, the system may use a double rinse process to washthe caustic from the PET polymer flakes.

In various embodiments, the system may be adapted to ensure that the PETpolymer being processed into filament is substantially free of water(e.g., entirely free of water). At Step 150, the washed PET polymerflakes may be dried as an initial step in reducing the water content ofthe flakes. In various embodiments, the system may centrifugally dewaterthe flakes and then dry the flakes with hot air to at leastsubstantially remove any surface moisture. To further dry the flakes,the system may place the flakes into a pre-conditioner for between about20 and about 40 minutes (e.g., about 30 minutes) during which thepre-conditioner blows the surface water off of the flakes. In particularembodiments, interstitial water may remain within the flakes. In variousembodiments, the system may feed these “wet” flakes (e.g., flakescomprising interstitial water) into an extruder (e.g., as describedherein), which may include a vacuum setup designed to remove—among otherthings—the interstitial water that remains present in the flakesfollowing the relatively quick drying process described as part ofMethod 100.

At Step 160, the system may remove further contaminants from thisresultant, dried “clean flake” using, for example, an electrostaticseparation system (e.g., an electrostatic separator from Carpco, Inc. ofJacksonville, Fla.) and/or a flake metal detection system (e.g., an MSSMetal Sorting System) to further remove any metal contaminants thatremain in the flake. In various embodiments, the system may also, orinstead, use an air separation process to remove any remaining labelfragments from the clean flake. The system may also color sort the PETpolymer flake at Step 160 to remove further contaminants. In variousembodiments, the system may process the flake using a flake colorsorting step (e.g., using an OPTIMIX machine from TSM Control Systems ofDundalk, Ireland) to remove any color contaminants that may be remainingin the flake. In various embodiments, the system may use anelectro-optical flake sorter based at least in part on Raman technology(e.g., a Powersort 200 from Unisensor Sensorsysteme GmbH of Karlsruhe,Germany) that performs a polymer separation to remove any non-PETpolymers remaining in the flake. At this step, the system may alsofurther remove any remaining metal contaminants and color contaminants.

For further contaminant removal, in various embodiments, at Step 160,the system may feed washed flakes down a conveyor and scan such flakeswith a high-speed laser system. In various embodiments, the system mayutilize one or more particular lasers that may be configured to detectthe presence of particular contaminants (e.g., PVC or Aluminum). Flakesthat are identified as not consisting essentially of PET polymer may beblown from the main stream of flakes with air jets.

In various embodiments, a system using the steps of Method 100 maydeliver substantially clean (e.g., clean) PET polymer flake comprisingless than about 50 parts per million PVC (e.g., 25 ppm PVC) and lessthan about 15 parts per million metals for use in the extrusion processembodiments described herein. In various embodiments, the resultinglevel of non-PET flakes is less than 25 ppm. Note that the steps ofMethod 100 may be performed in any order and in combination with anyother steps or functions. Moreover, any aspect of any step of Method 100may be performed separately and independently from any other aspect ofMethod 100. All such embodiments are contemplated as within the scope ofthe instant disclosure.

Flake Melting and Purification Process

In particular embodiments, a system according to various embodiments mayprocess polymer flakes as described above and then use such flakes togenerate molten recycled PET polymer. The system may perform one or morepurification processes to prepare such a polymer to be used to createBCF that may be used in the manufacture of carpet.

FIG. 2 illustrates a block diagram representing an exemplary Method 200for processing polymer flakes into BCF according to various embodiments.At Step 210, the system may acquire PET polymer flakes, such as recycledPET polymer flakes. In various embodiments, recycled PET polymer flakes,such as those that may be generated by Method 100 of FIG. 1, may be“wet.” For example, while surface water may have been substantiallyremoved (e.g., fully removed) from such flakes, interstitial water mayremain in the flakes.

At Step 220, the system may apply heat to the flakes to melt them into aliquid form that may be used as a single stream of melted polymer. Thismay be performed in a Melt Processing Unit 340 of the system (e.g., inan extruder that is part of the Melt Processing Unit 340). In variousembodiments, the system may melt the flakes in a first section of a MeltProcessing Unit 340 having multiple sections, forming a single stream ofmelted polymer that may be provided to other sections of the MeltProcessing Unit 340. In various embodiments, the system may also addcolor additives and mix the polymer in this section of the MeltProcessing Unit 340 as described herein.

At Step 230, the system may separate the single stream of melted polymerinto multiple streams of melted polymer to increase the surface area ofthe polymer melt for moisture removal purposes and for improving theintrinsic viscosity of the melt. For example, the system may feed thesingle stream of melted polymer into a multiple stream section of theMelt Processing Unit 340, where the system may separate the singlestream of melted polymer into a plurality of different streams. Forexample, in various embodiments, the system may separate a single streamof melted polymer into between about 5 and about 15 streams (e.g., 8streams); between about 100 and 500 streams; between about 1000 and 5000streams (e.g., 1,000, 3,000 or 5,000 streams), or more streams in themultiple stream section of the Melt Processing Unit 340. According toone embodiment, the system separates the single stream of melted polymerinto between approximately 2,000 and approximately 4,000 polymerstreams. The system may separate the single stream of melted polymerinto the multiple streams of melted polymer at an inlet of the multiplestream section of the Melt Processing Unit 340, or at any other suitablelocation. Such an inlet may utilize any type of mechanism or apparatusthat may be configured to separate a single stream of melted polymerreceived from a first section of the Melt Processing Unit 340 into adesired number of multiple streams of melted polymer in the multiplestream section of the Melt Processing Unit 340. For example, an inlet ina first section of a Melt Processing Unit 340 may include a separationelement that may comprise an extrusion die that defines a plurality ofholes corresponding to a desired number of multiple streams of meltedpolymer. According to one embodiment, the plate may define holescorresponding to approximately 3,000 multiple streams of melted polymer.Any other type of separation element that is capable of separating asingle stream of melted polymer into multiple streams of melted polymeris contemplated as within the scope of the disclosure.

The diameter of the holes used to separate the single stream of meltedpolymer into the multiple streams of melted polymer may depend on adesired flow rate and surface area of the multiple streams of meltedpolymer as they free fall through the multiple stream section of theMelt Processing Unit 340 toward an outlet of the multiple stream sectionof the Melt Processing Unit 340 and into a second, or receiving, sectionof the Melt Processing Unit 340. According to one embodiment, thediameter of the holes is less than 0.5 mm. According to otherembodiments, the diameter of the holes is between approximately 0.05 mmand 0.5 mm. According to still other embodiments, the diameter of theholes is between approximately 0.1 mm and 0.3 mm. The shape of the holesused to separate the single stream of melted polymer into the multiplestreams of melted polymer may be any suitable aperture shape (e.g.,circular, oval, polygonal, star shaped, etc.).

After the single stream of melted polymer is split into multiple streamsof melted polymer at the inlet of the multiple stream section of theMelt Processing Unit 340, the multiple streams of melted polymer mayfall downward, assisted by gravity, toward an outlet of the multiplestream section of the Melt Processing Unit 340. The distance between theinlet of a multiple stream section and the outlet of a multiple streamsection may be selected based on the desired characteristics of thesingle polymer stream created using the multiple streams of meltedpolymer passing through the multiple stream section of the MeltProcessing Unit 340. This is because, in various embodiments, thedistance between the multiple stream section's inlet and outlet maydefine how long each individual polymer stream is exposed to lowpressure. As noted herein, the interior of the multiple stream sectionof the Melt Processing Unit 340 may be subjected to low pressures (forexample, at Step 240 of Method 200), which may also affect the desiredcharacteristics of the single polymer stream created using the multiplestreams of melted polymer. For example, the distance between an inlet ofa multiple stream section and an outlet of a multiple stream section maybe between approximately 1 meter and approximately 4 meters, or betweenapproximately 3.3 feet and approximately 13.1 feet. According to aparticular embodiment, the distance between an inlet of a multiplestream section and an outlet of a multiple stream section may beapproximately 2 meters or 6.6 feet.

By splitting the polymer melt into a large number of polymer streams atStep 230, the system may significantly increase the surface area of themelted polymer that may be exposed to an interior portion of a chamberwithin the Melt Processing Unit 340 (e.g., a chamber that defines atleast a portion of the multiple stream section of the Melt ProcessingUnit 340.

At Step 240, lowered pressure (e.g., a vacuum or a near-vacuum) may beapplied to the multiple streams of melted polymer in the multiple streamsection of the Melt Processing Unit 340. The system may use a vacuumpump connected to the multiple stream section of the Melt ProcessingUnit 340 to reduce the pressure within that section. For example, themultiple stream section of the Melt Processing Unit 340 may be fittedwith a vacuum pump that may be attached to a vacuum attachment portionof multiple stream section of the Melt Processing Unit 340 so that thevacuum pump is in communication with the interior of the Melt ProcessingUnit 340 via a suitable opening in the housing of the multiple streamsection of the Melt Processing Unit 340. In various other embodiments,the multiple stream section of the Melt Processing Unit 340 may befitted with multiple vacuum pumps, as described herein.

As the system maintains a reduced pressure within the multiple streamsection of the Melt Processing Unit 340 using one or more vacuum pumps,the increased surface area of the polymer melt achieved using multiplestreams of melted polymer causes water and other contaminates toevaporate from the surface of the polymer melt as the multiple streamsof melted polymer fall through the multiple stream section of the MeltProcessing Unit 340 from the inlet of the multiple stream section of theMelt Processing Unit 340 towards the outlet of the multiple streamsection of the Melt Processing Unit 340. By applying lowered pressure tothe multiple streams of melted polymer as they travel through themultiple stream section of the Melt Processing Unit 340, the systemimproves the intrinsic viscosity of the recycled PET polymer as thepolymer chains in the polymer reconnect and extend the chain length.

The pressure applied to the multiple streams of melted polymer in themultiple stream section of the Melt Processing Unit 340 may beapproximately 1 millibar or less. In an embodiment, the pressure appliedto the multiple streams of melted polymer in the multiple stream sectionof the Melt Processing Unit 340 may be between approximately 0 millibarsand approximately 1.5 millibars. In another embodiment, the pressureapplied to the multiple streams of melted polymer in the multiple streamsection of the Melt Processing Unit 340 may be between approximately 0.5millibars and approximately 5 millibars. In another embodiment, thepressure applied to the multiple streams of melted polymer in themultiple stream section of the Melt Processing Unit 340 may be betweenapproximately 0.5 millibars and 1.2 millibars. Any desired pressuresdescribed herein are equally applicable to the embodiments describedhere with respect to the of the multiple stream section of the MeltProcessing Unit 340 used in Method 200.

At Step 250, at an outlet of the multiple stream section of the MeltProcessing Unit 340 (or at any other suitable location within the MeltProcessing Unit 340), the system may recombine the multiple streams ofmelted polymer into a single polymer stream. The system may feed thissingle stream into a receiving section of the Melt Processing Unit 340that may, at Step 260, provide the polymer to one or more spinningmachines. In an embodiment, at Step 250, the system may feed themultiple streams of melted polymer into an extruder section fortransporting the melted polymer away from the multiple stream section ofthe Melt Processing Unit 340 and for forming the multiple streams ofmelted polymer into a single polymer stream. The system may run thesingle polymer stream through a filtration system that may include atleast one filter. The system may also process the stream of meltedpolymer in any other desired manner, including as described herein.

At Step 270, after receiving the single polymer stream at Step 260, aspinning machine may use polymer from the single polymer stream tocreate BCF fiber for use in carpet manufacture. Alternatively, thesystem may route one or more of the multiple streams of melted polymerfrom the multiple stream section of the Melt Processing Unit 340directly into a spinning machine. In another embodiment, the system mayroute one or more of the multiple streams of melted polymer from themultiple stream section of the Melt Processing Unit 340 into a spinningmachine via a filtration system.

General PET Polymer Processing System

FIG. 3A illustrates a block diagram representing exemplary System 300for processing PET polymer into BCF. System 300 may use PET from anysuitable source, such as recycled PET polymer bottles. The source PETpolymer may be processed, for example, as described above in regard toMethod 100 of FIG. 1, in preparation for grinding into flakes. Followingsuch processing, the System 300 may grind the source PET polymer intoflakes at Grinding Unit 310. In various embodiments, the Grinding Unit310 may perform a granulation of the source PET polymer (e.g., using a50B Granulator machine from Cumberland Engineering Corporation of NewBerlin, Wis.) to size-reduce (e.g., grind or shred) the source PETpolymer down to a size of less than approximately one half of an inch.In various other embodiments, the Grinding Unit 310 may reduce thesource PET polymer to relatively smaller prices that may be greater thanapproximately one half of an inch.

Washing Unit 320 may wash the flakes generated by Grinding Unit 310.Washing Unit 320 may mix the “dirty flakes” generated by Grinding Unit310 into a series of wash tanks. Washing Unit 320 may employ an aqueousdensity separation as part of the its wash process to separate outcontaminants such as bottle caps (e.g., olefin bottle caps) which may,for example, be present in the dirty flake as remnants from recycled PETbottles. Washing Unit 320 may take advantage of the higher specificgravity of polymer PET flakes to separate such flakes from othermaterial in the dirty flake. Washing Unit 320 may wash the flakes in aheated caustic bath (e.g., heated to about 190 degrees Fahrenheit) thatWashing Unit 320 may maintain at a concentration of between about 0.6%and about 1.2% sodium hydroxide. In various embodiments, soapsurfactants and/or defoaming agents may be added to such a caustic bath,for example, to further increase the separation and cleaning of theflakes. Washing Unit 320 may utilize a double rinse system to wash thecaustic from the flakes.

In various embodiments, Washing Unit 320 may centrifugally dewater andthen dry the washed flake with hot air to at least substantially removeany surface moisture. Washing unit 320 may further process the resultant“clean flake” using an electrostatic separation system (e.g., anelectrostatic separator from Carpco, Inc. of Jacksonville, Fla.) and aflake metal detection system (e.g., an MSS Metal Sorting System) tofurther remove any metal contaminants that remain in the flake. Inparticular embodiments, Washing Unit 320 may use air separation toremove any remaining label remnants from the clean flake. In variousembodiments, Washing Unit 320 may perform a flake color sorting step(e.g., using an OPTIMIX machine from TSM Control Systems of Dundalk,Ireland) to remove any remaining color contaminants remaining in theflake. In various embodiments, Washing Unit 320 may use anelectro-optical flake sorter based at least in part on Raman technology(e.g., a Powersort 200 from Unisensor Sensorsysteme GmbH of Karlsruhe,Germany) to perform polymer separation to remove any non-PET polymersremaining in the flake. This step may also further remove any remainingmetal contaminants and color contaminants. The output of Washing Unit320 may be substantially clean (e.g., clean) PET polymer flake havingless than about 50 parts per million PVC (e.g., 25 ppm PVC) and lessthan about 15 parts per million metals.

After the washing step, System 300 may provide the flakes to ScanningUnit 330. In various embodiments, System 300 may feed flakes fromWashing Unit 320 down a conveyor for scanning by Scanning Unit 330 usinga high-speed laser system. Scanning Unit 330 may utilize particularlasers configured to detect the presence of particular contaminants(e.g., PVC, aluminum, other metals or polymers, etc.). Scanning Unit 330may remove (e.g., by blowing with air jets) any flakes from a mainstream of flakes that are identified by Scanning Unit 330 as notconsisting essentially of PET polymer. In various embodiments, theresulting level of non-PET flakes in the remaining flakes is less than25 ppm.

System 300 may provide the flakes processed by the Scanning Unit 330 tothe Melt Processing Unit 340 to generate a molten PET polymer. System300 and Melt Processing Unit 340 may perform one or more purificationprocesses to prepare such a polymer to be used to create BCF that may beused in the manufacture of carpet.

Melt Processing Unit 340 may apply heat to PET polymer flakes to meltthem into a liquid single stream of melted polymer. Melt Processing Unit340 may perform this melting process in a chamber of a system forprocessing polymer as described herein, such as an extruder. In variousembodiments, Melt Processing Unit 340 may melt the flakes in a firstsection of Melt Processing Unit 340 to form a single stream of meltedpolymer that may be provided to other sections of the Melt ProcessingUnit 340. In various embodiments, Melt Processing Unit 340 may also addcolor additives and mix the polymer in a section of the Melt ProcessingUnit 340.

Melt Processing Unit 340 may separate a single stream of melted polymerinto multiple streams of melted polymer. This separation may increasethe exposed surface area of polymer melt, thereby allowing for increasedmoisture removal. The separation of a single stream of melted polymerinto multiple streams may also facilitate System 300's assessment andmanipulation of the intrinsic viscosity and/or the moisture level of themelt. For example, System 300 may feed a single stream of melted polymerinto a multiple stream section of Melt Processing Unit 340, where thesingle stream of melted polymer may be separated into a number ofdifferent streams. In various embodiments, System 300 may separate asingle stream of melted polymer into 8, 100, 500, 1,000, 3,000, 5,000 ormore streams in a multiple stream section of Melt Processing Unit 340.According to one embodiment, the Melt Processing Unit 340 of System 300may separate a single stream of melted polymer into betweenapproximately 2,000 and approximately 4,000 polymer streams.

The Melt Processing Unit 340 may separate a single stream of meltedpolymer into multiple streams of melted polymer at an inlet of amultiple stream section of a Melt Processing Unit 340, or any otherlocation within the Melt Processing Unit 340. Such an inlet may utilizeany type of mechanism or apparatus that may be configured to separate asingle stream of melted polymer received from a first section of theMelt Processing Unit 340 into a desired number of multiple streams ofmelted polymer in the multiple stream section of the Melt ProcessingUnit 340. For example, an inlet in a first section of a Melt ProcessingUnit 340 may include an extrusion die defining a number of holescorresponding to a desired number of multiple streams of melted polymer.According to one embodiment, the die may define holes corresponding toapproximately 3,000 multiple streams of melted polymer. In anotherembodiment, the die may define holes corresponding to between about2,000 and about 4,000 multiple streams of melted polymer.

The diameter of the holes used by the Melt Processing Unit 340 toseparate a single stream of melted polymer into multiple streams ofmelted polymer may depend on a desired flow rate and surface area of themultiple streams of melted polymer, for example, as they free fallthrough the multiple stream section of the chamber to a receivingsection of the Melt Processing Unit 340. According to one embodiment,the diameter of the holes is less than about 0.5 mm. According toanother embodiment, the diameter of the holes is between approximately0.05 mm and approximately 0.5 mm. According to yet another embodiment,the diameter of the holes is between approximately 0.1 mm andapproximately 0.3 mm. The shape of the holes used by the Melt ProcessingUnit 340 to separate a single stream of melted polymer into the multiplestreams of melted polymer may be any desired aperture shape (e.g.,circular, oval, polygonal, star shaped, etc.). In various embodiments,all holes used by the Melt Processing Unit 340 to separate a singlestream of melted polymer into the multiple streams of melted polymer arethe same shape, while in other embodiments, a portion of the holes usedby the Melt Processing Unit 340 to separate a single stream of meltedpolymer into the multiple streams of melted polymer may have a shapethat differs from the shape of other holes.

After System 300 separates a single stream of melted polymer is intomultiple streams of melted polymer at an inlet of a multiple streamsection of the Melt Processing Unit 340, System 300 may allow themultiple streams of melted polymer to fall downward, assisted bygravity, toward an outlet of the multiple stream section of the MeltProcessing Unit 340. As discussed above, in various embodiments, thedistance between an inlet of a multiple stream section of the MeltProcessing Unit 340 chamber and an outlet of such a multiple streamsection may depend on desired characteristics of the single polymerstream resulting from processing by the Melt Processing Unit 340. Asnoted herein, the multiple stream section may be subjected to lowpressures which may affect the desired characteristics of the singlepolymer stream created using the multiple streams of melted polymer. Forexample, the distance between an inlet of a multiple stream section of aMelt Processing Unit 340 and an outlet of such a multiple stream sectionmay be between approximately 1 meter and approximately 4 meters, orbetween approximately 3.3 feet and approximately 13.1 feet. According toanother embodiment, the distance between an inlet of a multiple streamsection of a Melt Processing Unit 340 and an outlet of such a multiplestream section may be approximately 2 meters or 6.6 feet.

By splitting a polymer melt into a large number of polymer streams,System 300 may significantly increase the surface area of the meltedpolymer that may be exposed to a low pressure within an interior of thechamber of the multiple stream section of the Melt Processing Unit 340.The Melt Processing Unit 340 may use a vacuum pump connected to themultiple stream section of a Melt Processing Unit 340 chamber to reducethe pressure within that section. For example, the multiple streamsection of the Melt Processing Unit 340 chamber may be fitted with avacuum pump that may be attached to a vacuum attachment portion of themultiple stream section of such a chamber so that the vacuum pump is incommunication with the interior of the chamber via a suitable opening inthe housing of the multiple stream section of the chamber. In variousembodiments, the multiple stream section of the chamber may be fittedwith multiple vacuum pumps, as described herein.

As System 300 maintains a reduced pressure in the multiple streamsection of a Melt Processing Unit 340 chamber using one or more vacuumpumps, the increased surface area of the polymer melt achieved usingmultiple streams of melted polymer facilitates the evaporation of waterand other contaminates from the surface of the polymer melt as themultiple streams of melted polymer fall through the multiple streamsection of the Melt Processing Unit 340 chamber from the inlet of thatsection toward the outlet of that section. By applying lowered pressureto the multiple streams of melted polymer as it travels through themultiple stream section of such a chamber, the system improves theintrinsic viscosity of the melted polymer as the polymer chains in thepolymer reconnect and extend the chain length.

The pressure applied to multiple streams of melted polymer in a multiplestream section of the Melt Processing Unit 340 chamber may be betweenapproximately 0 millibars and approximately 1 millibar. In anembodiment, the pressure applied to multiple streams of melted polymerin a multiple stream section of the Melt Processing Unit 340 chamber maybe between approximately 0 millibars and approximately 1.5 millibars. Inanother embodiment, the pressure applied to multiple streams of meltedpolymer in a multiple stream section of the Melt Processing Unit 340chamber may be between approximately 0.5 millibars and approximately 5millibars. In another embodiment, the pressure applied to multiplestreams of melted polymer in a multiple stream section of a MeltProcessing Unit 340 chamber may be between approximately 0.5 millibarsand approximately 1.2 millibars. Any desired pressures described hereinare equally applicable to the embodiments described here with respect tothe multiple stream section of a Melt Processing Unit 340 chamber thatmay be used in a system such as System 300.

System 300, at an outlet of a multiple stream section of a MeltProcessing Unit 340 chamber (or other suitable location), may recombinemultiple streams of melted polymer into a single polymer stream. System300 may feed this single stream into a receiving section of a MeltProcessing Unit 340 chamber and may then provide the polymer to one ormore Spinning Machines 350 for spinning into BCF fibers. In anembodiment, System 300 may feed multiple streams of melted polymer intoan extruder section for transporting the melted polymer away from themultiple stream section of the Melt Processing Unit 340 chamber and forforming the multiple streams of melted polymer into a single polymerstream. In this embodiment, the extruder itself may be understood to bethe “outlet” of the Melt Processing Unit 340 since the extruder receivesthe fallen polymer material and transports it out of the multi-streamsection of the Melt Processing Unit. In various embodiments, theextruder is positioned vertically immediately below a device that isused to divide the polymer melt into multiple streams so that themultiple streams can fall directly from the device into the extruderunder the weight of gravity.

System 300 may process a single polymer stream through a filtrationsystem that may include at least one filter. System 300 may also, orinstead, process a stream of melted polymer in any desired manner,including as described herein. After receiving a single polymer stream,the Spinning Machine 350 may use polymer from the single polymer streamto create BCF fibers for use in carpet manufacture. Alternatively, or inaddition, System 300 may route one or more of the multiple streams ofmelted polymer directly from the multiple stream section of the MeltProcessing Unit 340 chamber into the one or more Spinning Machines 350.In another embodiment, System 300 may route one or more of the multiplestreams of melted polymer from the multiple stream section of the MeltProcessing Unit 340 chamber into the Spinning Machine 350 via afiltration system.

In various embodiments, the one or more Spinning Machines 350 may beconfigured to turn molten polymer into bulked continuous filament. Invarious embodiments, the output of the Melt Processing Unit 340 isconnected substantially directly (e.g., directly) to the input of theone or more Spinning Machines 350 so that molten polymer from the MeltProcessing Unit 340 is fed directly into the one or more SpinningMachines 350. This process may be advantageous because molten polymermay, in certain embodiments, not need to be cooled and formed intopellets after extrusion. In particular embodiments, not cooling andforming the recycled molten polymer into pellets serves to avoidpotential chain scission in the polymer that might lower the polymer'sintrinsic viscosity. In alternative embodiments, polymer from the outputof the Melt Processing Unit 340 is cooled and formed into pellets andthe pellets are later formed into BCF by the one or more SpinningMachines 350.

Each of the one or more Spinning Machines 350 may extrude molten polymerthrough small holes in a spinneret in order to produce carpet yarnfilament from the polymer. In particular embodiments, the moltenrecycled PET polymer cools after leaving the spinneret. The carpet yarnmay then be taken up by rollers and ultimately turned into filament thatis used to produce carpet. In various embodiments, the carpet yarnproduced by the Spinning Machine 350 may have a tenacity of betweenabout 3 gram-force per unit denier (gf/den) and about 9 gf/den. Inparticular embodiments, the resulting carpet yarn has a tenacity of atleast about 3 gf/den.

The one or more Spinning Machines 350, and other spinning machinescontemplated for use with the disclosed embodiments, may include theSytec One spinning machine manufactured by Oerlika Neumag ofNeumuenster, Germany. The Sytec One machine may be especially adaptedfor hard-to-run fibers, such as nylon or solution-dyed fibers, where thefilaments are prone to breakage during processing. In variousembodiments, the Sytec One machine keeps the runs downstream of thespinneret as straight as possible, uses only one threadline, and isdesigned to be quick to rethread if there are filament breaks.

Although the example described above describes using the Sytec Onespinning machine to produce carpet yarn filament from the polymer, itshould be understood that any other suitable spinning machine may beused. Such spinning machines may include, for example, any suitableone-threadline or three-threadline spinning machine made by OerlikaNeumag of Neumuenster, Germany or any other company.

In various embodiments, the improved strength of the recycled PETpolymer generated using the process above allows it to be run at higherspeeds through the Spinning Machine 350 than would be possible usingpure virgin PET polymer. This may allow for higher processing speedsthan are possible when using virgin PET polymer.

FIG. 3B illustrates the operation of an exemplary Melt Processing Unit340. Melt Processing Unit 340 may melt polymer flakes, for example,received from Scanning Unit 330 or from another source of polymer flake.The Melt Processing Unit 340 may use the resultant molten polymer togenerate a single stream of polymer melt 341. To generate such a singlestream of polymer melt, the Melt Processing Unit 340 may apply heat toPET polymer flakes to melt them into a liquid single stream of meltedpolymer. The Melt Processing Unit 340 may perform this melting processin a chamber dedicated to melting polymer flakes. In some embodiments,this chamber may be an extruder or a section of an extruder.Alternatively, the Melt Processing Unit 340 may melt the flakes in afirst section of a chamber having multiple sections. The Melt ProcessingUnit 340 may provide the single stream of melted polymer to anotherchamber (or another chamber section) of the Melt Processing Unit 340,such as multiple stream chamber 345, for splitting into multiplestreams. In various embodiments, the Melt Processing Unit 340 may alsoadd color additives and mix the polymer in chamber or section 341.

As discussed above, in various embodiments, the single stream of meltedpolymer may be split into multiple streams of melted polymer byseparation element 342. By separating the single stream of polymer intomultiple streams, the surface area of polymer melt may be increased(e.g., greatly increased) and therefore the removal of moisture andimpurities from the polymer melt may be enhanced. Separating the singlestream of melted polymer into multiple streams may also assist inmeasuring and manipulating the intrinsic viscosity and/or the moisturelevel of the melt. In various embodiments, at separation element 342,the single stream of polymer melt may be separated into any suitablenumber of streams (e.g., 4-10, 50-100, 500-1000, 1,000-5,000 or morestreams) in the multiple stream chamber 345 of the Melt Processing Unit340. According to one embodiment, the Melt Processing Unit 340, usingthe separation element 342, may separate a single stream of meltedpolymer into between approximately 2,000 and approximately 4,000 polymerstreams.

The separation element 342 may be an extrusion die defining a pluralityof holes corresponding to a desired number of multiple streams of meltedpolymer. In various embodiments, the separation element 342 may defineapproximately 3,000 holes configured to generate a corresponding numberof multiple streams of melted polymer. In another embodiment, theseparation element 342 may define between approximately 2,000 andapproximately 4,000 holes configured to generate a corresponding numberof multiple streams of melted polymer. The diameter and shape of theholes configured at the separation element 342 may depend on a desiredflow rate and surface area of the multiple streams of melted polymer,for example, as they free fall through the multiple stream chamber 345to a recombination element 343.

The multiple streams of melted polymer may be allowed to fall downward,assisted by gravity, to recombination element 343 of the multiple streamchamber 345 of the Melt Processing Unit 340. As noted above, thedistance through which such multiple streams are to fall or otherwisetravel may depend on desired characteristics of the resultant singlepolymer stream. While travelling through the multiple stream chamber345, the multiple streams of polymer melt may be subjected to lowpressures which may affect the desired characteristics of the singlepolymer stream created using the multiple streams of melted polymer. Invarious embodiments, one or more vacuum pumps may be connected to themultiple stream chamber 345 to reduce and maintain a lowered pressurewithin that chamber. As the pressure in the multiple stream chamber 345is reduced, the evaporation of water and other contaminates from thesurface of the multiple streams of polymer melt may be facilitated asthe multiple streams of melted polymer fall through the multiple streamchamber 345. Also, as a result of the application of lowered pressure tothe multiple streams of melted polymer, the intrinsic viscosity of themelted polymer may be improved as the polymer chains in the polymerreconnect and extend the chain length.

The pressure applied to multiple streams of melted polymer in themultiple stream chamber 345 may, in various embodiments, be betweenabout 0 millibars and 1 millibar. In an embodiment, the pressure withinthe multiple stream chamber 345 may be between about 0 millibar andabout 1.5 millibars. In another embodiment, the pressure within themultiple stream chamber 345 may be between about 0.5 millibars and about5 millibars. In another embodiment, the pressure within the multiplestream chamber 345 may be between approximately 0.5 millibars andapproximately 1.2 millibars.

The multiple streams of melted polymer may be recombined at therecombination element 343 into a single polymer stream. Therecombination element 344 may be a chamber in which the multiple streamsare permitted to recombine into a single stream of melted polymer. Invarious embodiments, the recombination element 344 may comprise anextruder and/or a section and/or a chamber of an extruder. This singlestream may undergo further processing at 344, which may includefiltering and/or further purification, before being provided to one ormore spinning machines for spinning into BCF fibers or to anotherdestination for other processing.

Example PET Polymer Melt Processing Unit

FIG. 4 illustrates an exemplary PET Polymer Melt Processing Unit 400.According to various embodiments, a polymer melt or source of polymerfor melting may be generated by a Polymer Melt Source 402, for example,by a polymer melt generation system or device, which may include anextruder (e.g., a single-screw extruder). Polymer Melt Source 402 mayoperate in conjunction with a Color System 404 that adds colorconcentrate and/or otherwise manipulates the color of a resultingpolymer melt. A source of polymer may be provided to first section 410of Melt Processing Unit 400 via inlet 414. First section 410 of MeltProcessing Unit 400 may be configured with an extruder configured tomelt polymer flakes, generate a single stream of polymer melt 412, orotherwise provide the single stream of polymer melt 412 to the multiplestream section 420 of Melt Processing Unit 400.

In various embodiments, wet flakes may first be fed through an extruderor other system by Polymer Melt Source 402 that may generate sufficientheat (e.g., via shearing) to at least substantially melt (e.g., melt)the wet flakes. First section 410 may perform this function, or PolymerMelt Source 402 may perform this function. In various embodiments, firstsection 410 and Polymer Melt Source 402 may work in conjunction togenerate and/or color polymer melt to create the single stream ofpolymer melt 412 provided to the multiple stream section 420 of MeltProcessing Unit 400. The Melt Processing Unit 400 may be configured tooperate in conjunction with Color System 404 to add a solution dye colorconcentrate to the flakes (e.g., wet flakes) before feeding the flakesinto the first section 410 or other system for melting. In particularembodiments, the solution dye color concentrate may include any suitablecolor concentrate, which may, for example, result in a particular colorof polymer fiber following extrusion. As described herein, the ColorSystem 404 may be configured to adjust an amount of solution dye colorconcentrate added to the flakes prior to feeding the flakes through thefirst section 410 or other system for melting. For example, according tovarious embodiments, the Color System 404 is configured to add betweenabout two percent and about three percent color concentrate by mass tothe polymer flake. In other embodiments, the Color System 404 isconfigured to add between about zero percent and about three percentcolor concentrate by mass. In still other embodiments, the Color System404 is configured to add up to about six percent color concentrate bymass to the polymer flake. In some embodiments, the Color System 404 isconfigured to add between about one percent and about three percentcolor concentrate by mass to the polymer flake. In still otherembodiments, the Color System 404 is configured to add any suitableratio of color concentrate to polymer flake in order to achieve aparticular color of molten polymer (and ultimately polymer fiber)following extrusion.

Although in some embodiments, the Color System 404 may add colorconcentrate to polymer flake prior to feeding the flake through thefirst section 410 or other system for melting polymer flake, it shouldbe understood that in other embodiments, the Color System 404 may addcolor concentrate during any other suitable phase of the processesdescribed herein. For example, according to various embodiments, theColor System 404 may be configured to add the color concentratefollowing extrusion or melting of the polymer flake by the first section410 or other system for melting polymer flake but prior to feeding theresultant polymer melt through the multiple stream section 420 of MeltProcessing Unit 400. In still other embodiments, the Color System 404may add color concentrate after the flake has passed through themultiple stream section 420 of Melt Processing Unit 400 but prior topassing the polymer melt from Melt Processing Unit 400 onto a spinningmachine, as discussed herein. In still other embodiments, the ColorSystem 404 may add the color concentrate while the flakes and/or polymermelt are being extruded in an extruder or other system for melting,while the polymer melt is in multiple stream section 420 of MeltProcessing Unit 400, while the polymer melt is in receiving section 440of Melt Processing Unit 400, or at any other suitable phase of theprocess. In still other embodiments, the Color System 404 may add thecolor concentrate during one or more (e.g., a plurality) of the phasesof any of the processes described herein (e.g., the disclosed systemsmay add some color concentrate to the polymer flake prior to passing theflake through the first section 410 and then add additional solutioncolor concentrate following processing through the multiple streamsection 420. Following the addition of the color concentrate andextrusion or otherwise melting of the polymer provided by Polymer MeltSource 402, the resultant single stream of polymer melt 412 (e.g.,comprising the melted flakes and color concentrate), in variousembodiments, may then be fed through to the multiple stream section 420of Melt Processing Unit 400.

In the multiple stream section 420 of the Melt Processing Unit 400, thesingle stream of polymer melt 412 may be split into a plurality ofpolymer streams 418 (e.g., 418 a, 418 b, 418 c, . . . 418 n) to increasethe surface area of the polymer melt for water removal and intrinsicviscosity purposes. As noted, the separation of a single stream ofmelted polymer into multiple streams may also facilitate assessment andmanipulation of the intrinsic viscosity of the melt. In variousembodiments, the Melt Processing Unit 400 may separate single stream ofmelted polymer 412 into between 6 and 5000 or more streams (e.g., 8,100, 500, 1,000, 3,000, 5,000 or more streams) in multiple streamsection 420. According to one embodiment, the Melt Processing Unit 400may separate single stream of melted polymer 412 into betweenapproximately 2,000 and approximately 4,000 polymer streams 418.

The Melt Processing Unit 400 may separate single stream of meltedpolymer 412 into multiple streams of melted polymer 418 at separationelement 416 of multiple stream section 420. Such an element may utilizeany type of mechanism or apparatus that may be configured to separatesingle stream of melted polymer 412 received from a first section 410into a desired number of multiple streams of melted polymer 418 in themultiple stream section 420. For example, the separation element 416 mayinclude a plate that may have a number of holes corresponding to adesired number of multiple streams of melted polymer. According to oneembodiment, a plate configured at the separation element 416 may haveholes corresponding to approximately 3,000 multiple streams of meltedpolymer. In some embodiments, such a plate may have holes correspondingto between approximately 2,000 and approximately 4,000 multiple streamsof melted polymer.

The diameter of the holes used by a plate configured at the separationelement 416 to separate the single stream of melted polymer 412 into themultiple streams of melted polymer 418 may depend on a desired flow rateand surface area of the multiple streams of melted polymer, for example,as they free fall through the multiple stream section 420 to an outlet421 of the multiple stream section 420 and are provided to a second, orreceiving, section 430 of the Melt Processing Unit 400. According to oneembodiment, the diameter of the respective holes in plate 416 is lessthan 0.5 mm. According to another embodiment, the diameter of the holesin a plate configured at the separation element 416 is betweenapproximately 0.05 mm and approximately 0.5 mm. According to yet anotherembodiment, the diameter of the holes in a plate configured at theseparation element 416 is between approximately 0.1 mm and 0.3 mm. Theshape of the holes in such a plate may be any desired aperture shape(e.g., circular, oval, polygonal, star shaped, etc.). In variousembodiments, all holes in a plate configured at the separation element416 are the same shape, while in other embodiments, a portion of suchholes may have a shape that differs from the shape of other holes.

By splitting the polymer melt into a large number of polymer streams418, the surface area of the polymer exposed to multiple stream section420 of Melt Processing Unit 400 is significantly increased. As describedherein, a Vacuum Pump 422 may be connected to the multiple streamsection 420 of Melt Processing Unit 400 to reduce the pressure withinthe multiple stream section 420. In various embodiments, the Vacuum Pump422 may be attached to a vacuum attachment portion of the multiplestream section 420 so that the Vacuum Pump 422 is in communication withthe interior of the multiple stream section 420 via a suitable openingin the Melt Processing Unit 400's housing. In still other embodiments,the Melt Processing Unit 400 may be fitted with a series of vacuumpumps, as described herein. The reduced pressure generated by the VacuumPump 422 and the increased surface area of the polymer melt achieved bynumerous polymer streams 418 may facilitate the evaporation of water andother contaminates from the surface of the polymer melt as the polymerstreams 418 fall towards the outlet 421 and are provided to thereceiving section 430 of Melt Processing Unit 400. In doing so, theintrinsic viscosity of the recycled PET polymer may be improved as thepolymer chains in the polymer reconnect and extend the chain length. Thedesired pressures described herein with respect to other figures andembodiments are equally applicable to the embodiments described herewith respect to the multiple stream section 420 of Melt Processing Unit400.

Melt Processing Unit 400 may include the receiving section 430 where thepolymer streams 418 may be recombined into a single polymer stream andflow into a system (e.g., an extruder) for transporting material awayfrom the multiple stream section 420 of Melt Processing Unit 400. Invarious embodiments, the Melt Processing Unit 400 may run the resultantsingle stream of molten polymer through a Filtration System 434 that mayinclude at least one filter. After processing by the Melt ProcessingUnit 400, the resultant single stream of polymer melt may be processedaccording to any other embodiments described herein or in any othermanner. The single polymer stream may be routed from the Melt ProcessingUnit 400 directly into a spinning machine or to a spinning machine viaFiltration System 434.

Melt Processing Unit 400 may utilize a Viscosity Sensor 436 to sense themelt viscosity of the molten polymer stream following its passagethrough the Filtration System 434. In various embodiments, the ViscositySensor 436 measures the melt viscosity of the stream, for example, bymeasuring the stream's pressure drop across a known area. In particularembodiments, in response to measuring an intrinsic viscosity of thestream that is below a predetermined level (e.g., below about 0.8 g/dL),the Melt Processing Unit 400 may discard the portion of the stream withlow intrinsic viscosity and/or lower the pressure in the multiple streamsection 420 of Melt Processing Unit 400 in order to achieve a higherintrinsic viscosity in the polymer melt. For example, the ViscositySensor 436 may be in communication with the Vacuum Pump 422 and mayinstruct the Vacuum Pump 422 to adjust the pressure applied to themultiple stream section 420 of Melt Processing Unit 400 based on thedetected viscosity of the molten polymer stream. In particularembodiments, the Melt Processing Unit 400 may adjust the pressure in themultiple stream section 420 in a substantially automated manner (e.g.,automatically) using the Viscosity Sensor 436 in a computer-controlledfeedback control loop with the Vacuum Pump 422.

Melt Processing Unit 400 may utilize a Color Sensor 438 to determine acolor of the resultant polymer melt. In various embodiments, the ColorSensor 438 may include one or more spectrographs configured to separatelight shone through the polymer melt into a frequency spectrum todetermine the color of the polymer melt. In other embodiments, the ColorSensor 438 may include one or more cameras or other suitable imagingdevices configured to determine a color of the resultant polymer melt.In response to determining at the Color Sensor 438 that the color of thepolymer melt is a color other than a desired color (e.g., the polymermelt is lighter than desired, darker than desired, a color other thanthe desired color, etc.) the Melt Processing Unit 400 may discard theportion of the stream with the incorrect color. Alternatively, or inaddition, the Melt Processing Unit 400 may adjust an amount of colorconcentrate that is added to the flake and/or the polymer melt at theColor System 404 in order to adjust a color of the resultant polymermelt. For example, the Color Sensor 438 may be in communication with theColor System 404 and may instruct the Color System 404 to adjust thecolor concentrate(s) applied to the flakes and/or melt based on thedetected color of the resultant polymer stream. In particularembodiments, the Melt Processing Unit 400 may adjust the amount and typeof color concentrate used at Color System 404 in a substantiallyautomated manner (e.g., automatically) using the Color Sensor 438 in acomputer-controlled feedback control loop with the Color System 404.

Example Extruder for Melting and Purifying PET Polymer Flakes

In particular embodiments, an extruder may be used to turn the wetflakes described herein into a molten recycled PET polymer and/or toperform a number of purification processes to prepare a polymer to beturned into BCF for use in manufacturing carpet. FIG. 5 illustrates anexample extruder 500 that may be used in some embodiments. In particularembodiments, the Melt Processing Unit 340 may comprise this exampleextruder 500.

In various embodiments, polymer flakes may be generated from a source ofpolymer, such as recycled PET polymer containers. As noted above, theseflakes may be “wet” (e.g., surface water may have been substantiallyremoved (e.g., fully removed) from the flakes, but interstitial watermay remain in the flakes). In particular embodiments, the system mayfeed these wet flakes into an extruder 500. Example extruders that maybe used with a variety of embodiments include a twin screw extruder, amultiple screw extruder, a planetary extruder, a Multiple Rotating Screw(“MRS”) (e.g., as described in U.S. Published Patent Application2005/0047267, entitled “Extruder for Producing Molten PlasticMaterials”, which was published on Mar. 3, 2005, and which is herebyincorporated herein by reference), and any other suitable extrusionsystem. In a various embodiments, the disclosed systems and processesmay utilize a plurality of extruders configured in any suitablecombination (e.g., four twin screw extruders, three multiple screwextruders, etc.).

Exemplary extruder 500 may include a first single-screw extruder section510 that may feed material into a multiple screw section 520 and asecond single-screw extruder section 540 that may transport materialaway from the multiple screw section 520.

In various embodiments, wet flakes may be fed directly into the extruder500 substantially immediately (e.g., immediately) following a washingstep, such as the example washing steps described herein (e.g., withoutdrying the flakes or allowing the flakes to dry). By feeding wet flakesdirectly into the extruder 500 substantially immediately (e.g.,immediately) following a washing step, the disclosed embodiments mayconsume about 20% less energy than a system that substantially fullypre-dries the flakes before extrusion (e.g., a system that pre-dries theflakes by passing hot air over the wet flakes for a prolonged period oftime). Furthermore, by feeding the wet flakes directly into the extruder500 substantially immediately (e.g., immediately) following a washingstep, the disclosed embodiments may avoid the requirement to allow for aparticular period of time (e.g., up to eight hours) to fully dry theflakes (e.g., remove substantially all of the surface and interstitialwater from the flakes).

The system may first feed wet flakes through the extruder 500's firstsingle-screw extruder section 510, which may, for example, generatesufficient heat (e.g., via shearing) to at least substantially melt(e.g., melt) the wet flakes.

In various embodiments, the system may be further configured to add acolor concentrate (e.g., a solution dye color concentrate) to the flakes(e.g., wet flakes) before feeding the flakes into the first single-screwextruder section 510. A solution dye color concentrate used in anyembodiment described herein may include any suitable color concentrate,which may, for example, result in a particular color of polymer fiberfollowing processing according to disclosed embodiments. In particularembodiments, the color concentrate may comprise pelletized colorconcentrate as well as a carrier resin which may, for example, bind thecolorant to the polymer. In various embodiments, adding colorconcentrate to the flakes prior to melting and/or processing may resultin polymer filament that is at least partially impregnated (e.g.,impregnated) with a color pigment. Carpet produced from solution dyedfilament created according to such embodiments may be highly resistantto color loss through fading from sunlight, ozone, harsh cleaning agentssuch as bleach, or other factors.

The system may be configured to adjust an amount of color concentrate toadd to the flakes prior to feeding the flakes thought the firstsingle-screw extruder section 510. In particular embodiments, the systemmay be configured to add between about two percent and about threepercent color concentrate by mass to the polymer flake. In otherembodiments, the system may be configured to add between about zeropercent and about three percent color concentrate by mass to the polymerflake. In still other embodiments, the system may be configured to addup to about six percent color concentrate by mass to the polymer flake.In some embodiments, the system is configured to add between about onepercent and three percent color concentrate by mass to the polymerflake. In still other embodiments, the system is configured to add anysuitable ratio of color concentrate to polymer flake in order to achievea particular color of molten polymer (and ultimately polymer fiber)following extrusion.

Note that in various embodiments, color concentrate may be added duringany other suitable phase of any of the example processes described inthis document. For example, color concentrate may be added followingextrusion of the polymer flake by the first single-screw extrudersection 510 but prior to feeding the resultant polymer melt through theextruder 500's multiple screw section 520. In other embodiments, thesystem may add color concentrate after the flake has passed through theextruder 500's multiple screw section 520 but prior to passing thepolymer melt through the second single-screw extruder section 540. Instill other embodiments, they system may add color concentrate while theflakes and/or polymer melt are being extruded in the extruder 500'sfirst single-screw extruder section 510, multiple screw section 520,second single-screw extruder section 540, or at any other suitable phaseof the process. In still other embodiments, the system may add colorconcentrate during one or more (e.g., a plurality) of the phases of anyof the example processes described herein (e.g., the system may add somecolor concentrate to the polymer flake prior to passing the flakethrough the first single-screw extruder section 510 and may then addsome additional solution color concentrate following extrusion throughthe multiple screw section 520).

Following the addition of the color concentrate and extrusion by firstsingle-screw extruder section 510, the system may feed the resultantpolymer melt (e.g., comprising the melted flakes and color concentrate)into the extruder's 500's multiple screw section 520, in which theextruder 500 may separate the melt flow into a plurality of differentstreams (e.g., 4, 6, 8, or more streams) through a plurality of openchambers. FIG. 6 illustrates a detailed cutaway view of the multiplescrew section 520 according to a particular embodiment. In embodimentssuch as that shown in this figure, the multiple screw section 520separates the melt flow into eight different streams, which aresubsequently fed through eight satellite screws 525A-H. As may beunderstood from the figures, in particular embodiments, these satellitescrews 525A-H may be substantially parallel (e.g., parallel) to oneother and to a primary screw axis of the extruder 500.

In the multiple screw section 520, in various embodiments, the satellitescrews 525A-H may, for example, rotate faster than (e.g., about fourtimes faster than) in previous systems. As shown in FIG. 6, inparticular embodiments the satellite screws 525A-H may be arrangedwithin a single screw drum 528 that is mounted to rotate about itscentral axis. The satellite screws 525A-H may be configured to rotate ina direction that is opposite to the direction in which the single screwdrum 528 rotates. In various other embodiments, the satellite screws525A-H and the single screw drum 528 may rotate in the same direction.In particular embodiments, the rotation of the satellite screws 525A-Hmay be driven by a ring gear. Also, in various embodiments, the singlescrew drum 528 may rotate about four times faster than each individualsatellite screw 525A-H. In certain embodiments, the satellite screws525A-H each rotate at substantially similar (e.g., the same) speeds.

In various embodiments, the satellite screws 525A-H are housed withinrespective extruder barrels, which may, for example be about 30% open toan outer chamber of the multiple screw section 520. In particularembodiments, the rotation of the satellite screws 525A-H and singlescrew drum 528 may increase the surface exchange of the polymer melt(e.g., exposes more surface area of the melted polymer to the openchamber than in previous systems). In various embodiments, the multiplescrew section 520 may create a melt surface area that is, for example,between about twenty and about thirty times greater than the meltsurface area created by a co-rotating twin screw extruder. In aparticular embodiment, the multiple screw section 520 may create a meltsurface area that is, for example, about twenty-five times greater thanthe melt surface area created by a co-rotating twin screw extruder.

In various embodiments, the extruder 500's multiple screw section 520 isfitted with a vacuum pump (e.g., as described herein) that is attachedto a vacuum attachment portion of the multiple screw section 520 so thatthe vacuum pump is in communication with the interior of the multiplescrew section 520 via a suitable opening in the multiple screw section520's housing. In other embodiments, the multiple screw section 520 isfitted with a series of vacuum pumps. In particular embodiments, avacuum pump is configured to reduce the pressure within the interior ofthe multiple screw section 520 to a pressure that is between about 0.5millibars and about 5 millibars. In other particular embodiments, thevacuum pump is configured to reduce the pressure in the multiple screwsection 520 to between about 0 millibar and about 1.5 millibars (e.g.,between about 0 millibar and about 1 millibar). In other particularembodiments, the vacuum pump is configured to reduce the pressure in themultiple screw section 520 to between approximately 0.5 millibars and1.2 millibars. The low-pressure vacuum in the multiple screw section 520created by the vacuum pump may remove, among other things, volatileorganics present in the melted polymer as the melted polymer passesthrough the multiple screw section 520 and/or at least a portion of anyinterstitial water that was present in the wet flakes when the wetflakes entered the extruder 500. In various embodiments, thelow-pressure vacuum removes substantially all (e.g., all) of the waterand contaminants from the polymer stream.

In a particular example, the vacuum pump used to reduce the pressure inthe multiple screw section 520 (and in any other embodiment contemplatedherein) may include a plurality of (e.g., two or three) mechanical lobevacuum pumps (e.g., arranged in series) to reduce the pressure in themultiple screw section 520 to a suitable level (e.g., to a pressure ofabout 1.0 millibar, to between about 0.5 millibars and 1.2 millibars, orto between about 0.5 millibars and about 5 millibars). In otherembodiments, rather than using a multiple mechanical lobe vacuum pumparrangement, the system may use a vacuum pump that includes a jet vacuumpump that may be fitted to the extruder 500. In various embodiments,such a jet vacuum pump may be configured to achieve about 1 millibar ofpressure in the interior of the multiple screw section 520 and similardesired intrinsic viscosity results for the polymer melt as describedelsewhere herein. In other various embodiments, such a jet vacuum pumpmay be configured to achieve between about 0.5 millibars and 1.2millibars of pressure in the interior of the multiple screw section 520and similar desired intrinsic viscosity results for the polymer melt asdescribed elsewhere herein. In other various embodiments, such a jetvacuum pump may be configured to achieve between about 0.5 millibars andabout 5 millibars of pressure in the interior of the multiple screwsection 520 and similar desired intrinsic viscosity results for thepolymer melt as described elsewhere herein. Using a jet vacuum pump maybe advantageous because jet vacuum pumps are steam powered and thereforesubstantially self-cleaning (e.g., self-cleaning), thereby reducingrequired maintenance in comparison to mechanical lobe pumps (which may,for example, require repeated cleaning due to volatiles coming off thepolymer melt and condensing on the lobes of the pump). In a particularembodiment, the vacuum pump used with extruder 500 is a jet vacuum pumpis made by Arpuma GmbH of Bergheim, Germany.

In particular embodiments, after the molten polymer is run through themultiple screw section 520, the streams of molten polymer are recombinedand flow into the extruder 500's second single-screw extruder section540. In various embodiments, the resulting single stream of moltenpolymer may next be run through a filtration system that includes atleast one filter. Such a filtration system may include two levels offiltration (e.g., a 40 micron screen filter followed by a 25 micronscreen filter). Although, in various embodiments, water and volatileorganic impurities are removed during the vacuum process as discussedabove, particulate contaminates such as, for example, aluminumparticles, sand, dirt, and other contaminants may remain in the polymermelt. Thus, this filtration step may be advantageous in removingparticulate contaminates (e.g., particulate contaminates that were notremoved in the multiple screw section 520).

In particular embodiments, a viscosity sensor (e.g., as describedherein) may be used to sense a melt viscosity of the molten polymerstream, for example, following its passage through a filtration system.The system may utilize the viscosity sensor to measure the meltviscosity of a stream, for example, by measuring the stream's pressuredrop across a known area. In particular embodiments, in response tomeasuring an intrinsic viscosity of the stream that is below apredetermined level (e.g., below about 0.8 g/dL), the system may discardthe portion of the stream with low intrinsic viscosity and/or lower thepressure in the multiple screw section 520 in order to achieve a higherintrinsic viscosity in the polymer melt. In particular embodiments,decreasing the pressure in the multiple screw section 520 is executed ina substantially automated manner (e.g., automatically) using theviscosity sensor in a computer-controlled feedback control loop with avacuum pump.

Removing the water and contaminates from the polymer may improve theintrinsic viscosity of the recycled PET polymer by allowing polymerchains in the polymer to reconnect and extend the chain length. Inparticular embodiments, following its passage through the multiple screwsection 520 as operated in conjunction with an attached vacuum pump,recycled polymer melt has an intrinsic viscosity of at least about 0.79dL/g (e.g., of between about 0.79 dL/g and about 1.00 dL/g). Inparticular embodiments, passage through a low pressure multiple screwsection 520 purifies the recycled polymer melt (e.g., by removing thecontaminants and interstitial water). In particular embodiments, thewater removed by passing through a lowered pressure environment includesboth water from the wash water used to clean the recycled PET bottles asdescribed above, as well as from unreacted water generated by themelting of the PET polymer in, for example, the first single-screwextruder section 510 (e.g., interstitial water). In some embodiments,the majority of water present in the polymer is wash water, but somepercentage may be unreacted water.

Referring again to FIG. 5, a color sensor may be used to determine acolor of the resultant polymer melt created by the extruder 500. Invarious embodiments, the color sensor may include one or morespectrographs configured to separate light shone through the polymermelt into a frequency spectrum to determine the color of the polymermelt. In other embodiments, the color sensor may include one or morecameras or other suitable imaging devices configured to determine acolor of the resultant polymer melt. In particular embodiments, inresponse to determining that the color of the polymer melt is a colorother than a desired color (e.g., the polymer melt is lighter thandesired, darker than desired, a color other than the desired color,etc.) the system may discard the portion of the stream with theincorrect color and/or adjust an amount of color concentrate that isadded to the flake and/or the polymer melt upstream in order to adjust acolor of the resultant polymer melt. In particular embodiments,adjusting the amount of color concentrate is executed in a substantiallyautomated manner (e.g., automatically) using the color sensor in acomputer-controlled feedback control loop.

In particular embodiments, the resulting polymer is a recycled PETpolymer (e.g., obtained 100% from post-consumer PET products, such asPET bottles or containers) having a polymer quality that is suitable foruse in producing PET carpet filament using substantially only (e.g.,only) PET from recycled PET products. Spinning Machine 350 (or multiplespinning machines) may be configured to turn molten polymer into bulkedcontinuous filament. For example, in various embodiments, the output ofthe extruder 500 (e.g., of the second single-screw extruder section 540of the extruder 500) may be connected substantially directly (e.g.,directly) to the input of a spinning machine so that molten polymer fromthe extruder 500 may be fed directly into such a spinning machine. Thismay be advantageous because, unlike with recycled polymer that is mixedwith virgin PET polymer, molten polymer produced according to disclosedembodiments may not need to be cooled into pellets after extrusion. Inparticular embodiments, not having to cool the recycled molten polymerinto pellets allows the disclosed embodiments to avoid potential chainscission in the polymer that might lower the polymer's intrinsicviscosity.

A spinning machine (or multiple spinning machines) receiving moltenpolymer from the extruder 500 may extrude such molten polymer throughsmall holes in a spinneret in order to produce carpet yarn filament fromthe polymer. In particular embodiments, this molten recycled PET polymermay cool after leaving the spinneret. The carpet yarn may then beprovided to rollers and ultimately turned into filament that may be usedto produce carpet. In various embodiments, carpet yarn produced by aspinning machine using polymer produced according to the disclosedembodiments may have a tenacity between about 3 gram-force per unitdenier (gf/den) and about 9 gf/den. In particular embodiments, theresulting carpet yarn has a tenacity of at least about 3 gf/den.

Example Extrusion Process for Melting and Purifying PET Polymer Flakes

FIG. 7 depicts an example process flow 700 that illustrates the variousprocesses that may performed by an extruder in a particular embodiment.In the embodiment shown in this figure, the system may first feed wetflakes through a first single-screw extruder section 710, which may, forexample, generate sufficient heat (e.g., via shearing) to at leastsubstantially melt (e.g., melt) the wet flakes.

The system may further be configured to add a Solution Dye ColorConcentrate 715 to the flakes (e.g., wet flakes) before feeding theflakes into the first single-screw extruder section 710. The SolutionDye Color Concentrate 715 may include any suitable color concentrate,which may, for example, result in a particular color of polymer fiberfollowing extrusion. In particular embodiments, the color concentratemay be made up of pelletized color concentrate in combination with acarrier resin that may bind the colorant to the polymer. The system mayadd color concentrate to the flakes prior to extrusion to create polymerfilament that is at least partially impregnated (e.g., impregnated) witha color pigment. In various embodiments, carpet produced from solutiondyed filament may be resistant to color loss through fading fromsunlight, ozone, harsh cleaning agents such as bleach, or other factors.

The system may adjust an amount of Solution Dye Color Concentrate 715 tobe added to the flakes prior to feeding the flakes thought the firstsingle-screw extruder section 710. In particular embodiments, the systemis configured to add between about two percent and about three percentcolor concentrate by mass to the polymer flake. In other embodiments,the system is configured to add between about zero percent and aboutthree percent color concentrate by mass to the polymer flake. In stillother embodiments, the system is configured to add up to about sixpercent color concentrate by mass to the polymer flake. In still otherembodiments, the system is configured to add between about one percentand three percent color concentrate by mass to the polymer flake. Thesystem may be configured to add any suitable ratio of color concentrateto polymer flake in order to achieve a particular color of moltenpolymer (and ultimately polymer fiber) following extrusion.

Note that, while the Solution Dye Color Concentrate 715 is depicted asadded to the polymer flake prior to feeding the flake through the firstsingle-screw extruder section 710 in the figure, it should be understoodthat in other embodiments, the Solution Dye Color Concentrate 715 may beadded during any other suitable phase of the process described in thisdocument. For example, the system may be configured to add the SolutionDye Color Concentrate 715 following extrusion of the polymer flake bythe first single-screw extruder section 710 but prior to feeding theresultant polymer melt through the extruder's multiple screw section 720as discussed below. In still other embodiments, the system may add theSolution Dye Color Concentrate 715 after the flake has passed throughthe multiple screw section 720 prior to passing the polymer melt throughthe second single screw section 740 discussed below. In still otherembodiments, the system may add the Solution Dye Color Concentrate 715while the flakes and/or polymer melt are being extruded in the firstsingle-screw extruder section 710, the multiple screw section 720, thesecond single screw section 740, or at any other suitable phase of theprocess. In still other embodiments, the system may add the Solution DyeColor Concentrate 715 during one or more (e.g., a plurality) of thephases of the process described herein (e.g., the system may add someSolution Dye Color Concentrate 715 to the polymer flake prior to passingthe flake through the first single-screw extruder section 710 and someadditional Solution Dye Color Concentrate 715 following extrusionthrough the multiple screw section 720).

Following the addition of the color concentrate and extrusion by thefirst single-screw extruder section 710, the system may feed theresultant polymer melt (e.g., comprising the melted flakes and colorconcentrate) into the multiple screw section 720, in which the systemseparates the melt flow into a plurality of different streams (e.g., 4,6, 8, or more streams) through a plurality of open chambers. Inparticular embodiments, the melt flow may be separated into many streamsas described in regard to FIG. 4. In other embodiments, the melt flowmay be separated into various numbers of streams as described in regardto FIG. 5. In still other embodiments, a stream of melted polymer may beseparated into any number of streams to increase exposure of the polymerto a lowered pressure environment.

The multiple screw section 720 may be fitted with a Vacuum Pump 730 thatis attached to a vacuum attachment portion of the multiple screw section720 so that the Vacuum Pump 730 is in communication with the interior ofthe multiple screw section 720 via a suitable opening in the multiplescrew section 720's housing. In other embodiments, the multiple screwsection 720 is fitted with a series of vacuum pumps. In particularembodiments, the Vacuum Pump 730 is configured to reduce the pressurewithin the interior of the multiple screw section 720 to a pressure thatis between about 0.5 millibars and about 5 millibars. In otherembodiments, the Vacuum Pump 730 is configured to reduce the pressure inthe multiple screw section 720 to less than about 1.5 millibars (e.g.,about 1 millibar or less). In still other embodiments, the Vacuum Pump730 is configured to reduce the pressure in the multiple screw section720 to between about 0.5 millibars and 1.2 millibars. The low-pressurevacuum created by the Vacuum Pump 730 in the multiple screw section 720may remove volatile organics present in the melted polymer as the meltedpolymer passes through the multiple screw section 720 and/or at least aportion of any interstitial water that was present in the wet flakeswhen the wet flakes were provided to the system. In various embodiments,the low-pressure vacuum removes substantially all (e.g., all) of thewater and contaminants from the polymer stream.

In a particular example, the Vacuum Pump 730 comprises a plurality of(e.g., two or three) mechanical lobe vacuum pumps (e.g., arranged inseries) to reduce the pressure in the chamber to a suitable level (e.g.,to a pressure of about 1.0 millibar, to a pressure of between about 0.5millibars and about 5 millibars, to a pressure of between about 0.5millibars and 1.2 millibars, or to a pressure of less than about 1.5millibar). In other embodiments, rather than the multiple mechanicallobe vacuum pump arrangement discussed above, the Vacuum Pump 730includes a jet vacuum pump fit to the multiple screw section 720. Insuch embodiments, the jet vacuum pump is configured to achieve a desiredpressure (e.g., about 1 millibar, between about 0.5 millibars and about5 millibars, between about 0.5 millibars and 1.2 millibars, or less thanabout 1.5 millibar) in the interior of the multiple screw section 720and desired results such as those described herein regarding a resultingintrinsic viscosity of the polymer melt. In various embodiments, using ajet vacuum pump can be advantageous because jet vacuum pumps are steampowered and therefore substantially self-cleaning (e.g., self-cleaning),thereby reducing the maintenance required in comparison to mechanicallobe pumps (which may, for example, require repeated cleaning due tovolatiles coming off and condensing on the lobes of the pump). In aparticular embodiment, the Vacuum Pump 730 is a jet vacuum pump is madeby Arpuma GmbH of Bergheim, Germany.

In particular embodiments, after the molten polymer is run through themultiple screw section 720, the streams of molten polymer may berecombined and provided to the second single screw section 740. Invarious embodiments, the system sends the single stream of moltenpolymer through a Filtration System 750 that includes at least onefilter. In a particular embodiment, the Filtration System 750 includestwo levels of filtration (e.g., a 40 micron screen filter followed by a25 micron screen filter). Although, in various embodiments, water andvolatile organic impurities are removed during the vacuum process asdiscussed above, particulate contaminates such as, for example, aluminumparticles, sand, dirt, and other contaminants may remain in the polymermelt. Thus, this filtration step may be advantageous in removingparticulate contaminates (e.g., particulate contaminates that were notremoved in the multiple screw section 720).

In particular embodiments, a Viscosity Sensor 760 may be used to sensethe melt viscosity of the molten polymer stream following its passagethrough the Filtration System 750. In various embodiments, ViscositySensor 760 may measure the melt viscosity of the stream, for example, bymeasuring the stream's pressure drop across a known area. In particularembodiments, in response to measuring an intrinsic viscosity of thestream that is below a predetermined level (e.g., below about 0.8 g/dL),the system may discard the portion of the stream with low intrinsicviscosity and/or lower the pressure in the multiple screw section 720 inorder to achieve a higher intrinsic viscosity in the polymer melt. Inparticular embodiments, decreasing the pressure in the multiple screwsection 720 may be performed in a substantially automated manner (e.g.,automatically) using the Viscosity Sensor 760 in a computer-controlledfeedback control loop with the Vacuum Pump 730.

By removing the water and contaminates from the polymer, the systemimproves the intrinsic viscosity of the recycled PET polymer by allowingpolymer chains in the polymer to reconnect and extend the chain length.In particular embodiments, following its passage through the multiplescrew section 720 with its attached Vacuum Pump 730, the recycledpolymer melt has an intrinsic viscosity of at least about 0.79 dL/g(e.g., of between about 0.79 dL/g and about 1.00 dL/g). In particularembodiments, passage through the low pressure multiple screw section 720purifies the recycled polymer melt (e.g., by removing the contaminantsand interstitial water) and makes the recycled polymer substantiallystructurally similar to (e.g., structurally the same as) pure virgin PETpolymer. In particular embodiments, the water removed by the Vacuum Pump730 includes both water from the wash water used to clean the recycledPET bottles as described above, as well as from unreacted watergenerated by the melting of the PET polymer in the first single-screwextruder section 710 (e.g., interstitial water). In particularembodiments, the majority of water present in the polymer is wash water,but some percentage may be unreacted water.

The system may employ a Color Sensor 770 to determine a color of theresultant polymer melt. In various embodiments, the Color Sensor 770 mayutilize one or more spectrographs configured to separate light shonethrough the polymer melt into a frequency spectrum to determine thecolor of the polymer melt. In other embodiments, the Color Sensor 770may utilize one or more cameras or other suitable imaging devicesconfigured to determine a color of the resultant polymer melt. Inparticular embodiments, in response to determining that the color of thepolymer melt is a color other than a desired color (e.g., the polymermelt is lighter than desired, darker than desired, a color other thanthe desired color, etc.) the system may discard the portion of thestream with the incorrect color and/or adjust an amount of Solution DyeColor Concentrate 715 that is added to the flake and/or the polymer meltupstream in order to adjust a color of the resultant polymer melt. Inparticular embodiments, adjusting the amount of Solution Dye ColorConcentrate 715 may be performed in a substantially automated manner(e.g., automatically) using the Color Sensor 770 in acomputer-controlled feedback control loop.

In particular embodiments, the system of FIG. 7 may produce polymer froma recycled PET polymer (e.g., obtained 100% from post-consumer PETproducts, such as PET bottles or containers) that has a polymer qualitythat is suitable for use in producing PET carpet filament usingsubstantially only (e.g., only) PET from recycled PET products.

Use of a Crystallizer

In various embodiments, the disclosed systems and processes forproducing BCF may further include a crystallizing step that utilizes oneor more PET crystallizers. In particular embodiments, the system may beconfigured to perform the crystallization step on the ground flakesprior to processing the flakes through the one or more extruders ormelting systems (e.g., single screw extruder, multiple screw extruder,melt processing unit, MRS extruder, etc.). A PET crystallizer mayinclude a housing, a hopper screw (e.g., an auger) disposed at leastpartially within the housing, a stirring apparatus, one or more heatingelements, and one or more blowers.

In particular embodiments, the hopper screw may be any suitable screwconveyor (e.g., such as an Archimedes' screw) for moving liquid orgranular materials (e.g., such as PET flakes). In various embodiments,the hopper screw comprises a substantially cylindrical shaft and ahelical screw blade disposed along at least a portion of the cylindricalshaft. In particular embodiments, the substantially cylindrical shaftmay be configured to rotate the screw blade, causing that hopper screwto move material (e.g., the PET flakes) along the cylindrical shaft andinto the crystallizer housing. In other embodiments, the hopper screwcomprises any other suitable screw conveyer such as, for example, ashaftless spiral. In embodiments in which the hopper screw comprises ashaftless spiral, the shaftless spiral may be substantially fixed at oneend and free at the other end and configured to be driven at the fixedend. In various embodiments, the hopper screw is disposed at leastpartially within the crystallizer housing. A hopper screw may beconfigured to feed PET flakes into the crystallizer. In variousembodiments, the PET crystallizer is configured to feed the PET flakesinto the crystallizer using the hopper screw relatively slowly

In various embodiments, the crystallizer may include one or more heatingelements for raising a temperature within the crystallizer. The one ormore heating elements may include one or more electric heating elements,one or more gas-fired heating elements, and/or any other suitableheating elements or combinations thereof. In some embodiments, the oneor more heating elements may be substantially electrically powered. Invarious embodiments, the one or more heating elements comprise one ormore infra-red heating elements. In other embodiments, the one or moreheating elements may utilize natural gas such as, for example, propane.In particular embodiments, the one or more heating elements may beconfigured to raise a temperature within the crystallizer to betweenabout 100 degrees Fahrenheit and about 180 degrees Fahrenheit. In stillother embodiments, the one or more heating elements may be configured toraise a temperature within the crystallizer to between about 100 degreesCelsius and 180 degrees Celsius. In still other embodiments, the one ormore heating elements may be configured to raise a temperature withinthe crystallizer to between about 80 degrees Celsius and 120 degreesCelsius. In some embodiments, the one or more heating elements may beconfigured to maintain a temperature within the crystallizer that issubstantially about a maximum crystallization temperature of PET. Inparticular embodiments, the maximum crystallization temperature of PETis between about 140 degrees Celsius and about 230 degrees Celsius.

In various embodiments, the crystallizer may further include one or moreblowers configured to blow air over the flakes as the flakes passthrough the crystallizer. In particular embodiments, the one or moreblowers utilize any one or more suitable blowers for moving airsubstantially across a surface area of the flakes as the flakes passthrough the crystallizer. For example, in some embodiments, the one ormore blowers may include one or more suitable fans or other suitablemechanisms for moving air. In various embodiments, the one or moreblowers may be configured to blow air that has been at least partiallyheated by the one or more heating elements. In particular embodiments,the one or more blowers may be configured to blow air having atemperature of at least about 140 degrees Fahrenheit. In otherembodiments, the one or more blowers may be configured to blow airhaving a temperature of at least about 140 degrees Celsius. In otherembodiments, the one or more blowers are configured to maintain thetemperature in the crystallizer between about 140 degrees Fahrenheit andabout 180 degrees Fahrenheit. In other embodiments, the one or moreblowers are configured to maintain the temperature in the crystallizerbetween about 80 degrees Celsius and 120 degrees Celsius. In someembodiments, the one or more blowers are configured to blow hot air froma bottom portion of the crystallizer and draw air from an upper portionof the crystallizer.

In various embodiments, the crystallizer may include a stirringapparatus that comprises any suitable apparatus for stirring the PETflakes while the PET flakes are passing through the crystallizer. Invarious embodiments, the stirring apparatus may be operated, forexample, by any suitable gear motor. In a particular embodiment, thestirring apparatus comprises a suitable rod or other suitable mechanismmounted to rotate, or otherwise stir the PET flakes as the PET flakesare passing through the crystallizer. In other embodiments, the stirringapparatus may comprise any suitable tumbler, which may, for example,comprise a drum mounted to rotate via the gear motor such that the PETflakes are at least partially stirred and/or agitated while the PETflakes are within the drum. In still other embodiments, the stirringapparatus comprises one or more screws and/or augers configured torotate and stir the PET flakes. In particular embodiments, the stirringapparatus comprises the hopper screw.

As may be understood from this disclosure, the stirring apparatus isconfigured to agitate or stir the PET flakes as the one or more blowersblow air heated by the one or more heating elements across the PETflakes. In particular embodiments, the stirring apparatus may beconfigured to at least partially reduce agglomeration (e.g., sticking orclumping of the flake) while the flake is at least partiallycrystallizing in the crystallizer.

In particular embodiments, the crystallizer at least partially dries thesurface of the PET flakes. In various embodiments, the PET crystallizermay be configured to reduce a moisture content of the PET flakes toabout 50 ppm. In other embodiments, the PET crystallizer may beconfigured to reduce a moisture content of the PET flakes to betweenabout 30 ppm and 50 ppm.

In various embodiments, the use of drier flakes may enable the system torun the flakes through an extruder or melting system more slowly, whichmay allow for higher pressure within the system during extrusion (e.g.,may enable the system to maintain a higher pressure within a multiplestream section, rather than very low pressure). In various embodimentsof the process, the pressure regulation system may be configured tomaintain a pressure within an extruder or a melt processing system ofbetween about 0 millibars and about 25 millibars. In particularembodiments, such as embodiments in which the PET flakes have been runthrough a crystallizer before being extruded or melted, the pressureregulation system may be configured to maintain a pressure within anextruder or a melt processing system of between about 0 and about 18millibars. In other embodiments, the pressure regulation system may beconfigured to maintain a pressure within an extruder or a meltprocessing system between about 0 and about 12 millibars. In still otherembodiments, the pressure regulation system may be configured tomaintain a pressure within an extruder or a melt processing systembetween about 0 and about 8 millibars. In still other embodiments, thepressure regulation system may be configured to maintain a pressurewithin an extruder or a melt processing system between about 5 millibarsand about 10 millibars. In still other embodiments, the pressureregulation system may be configured to maintain a pressure within anextruder or a melt processing system between about between about 0.5millibars and about 5 millibars. In still other embodiments, thepressure regulation system may be configured to maintain a pressurewithin an extruder or a melt processing system between about 0.5millibars and 1.2 millibars. In still other embodiments, the pressureregulation system may be configured to maintain a pressure within anextruder or a melt processing system of less than about 1.5 millibars.In particular embodiments, the pressure regulation system may beconfigured to maintain a pressure within an extruder or a meltprocessing system at about 5 millibars, about 6 millibars, about 7millibars, about 8 millibars, about 9 millibars, or about any suitablepressure between about 0 millibars and about 25 millibars.

In particular embodiments, the crystallizer causes the flakes to atleast partially reduce in size, which may, for example, reduce apotential for the flakes to stick together. In particular embodiments,the crystallizer may particularly reduce stickiness of larger flakes,which may, for example, include flakes comprising portions of the groundPET bottles which may be thicker than other portions of the PET bottles(e.g., flakes ground from a threaded portion of the PET bottle on whicha cap would typically be screwed).

The Use of Colored PET Polymer and Color Additives

The disclosed systems and processes for manufacturing recycled bulkedcontinuous filament described herein may utilize colored (non-clear)post-consumer PET bottles (e.g., or other containers) in addition to theclear PET bottles described elsewhere herein. For example, in variousembodiments, the system may utilize blue, green, amber or any othersuitable colored containers (e.g., bottles) in the production ofrecycled BCF (e.g., rather than removing substantially all of thecolored PET from the recycled PET in the initial stages of the process).In certain embodiments, the process includes one or more additionalsteps that include, for example, adding one or more color additives(e.g., one or more solution dye color concentrates), which may dilute oralter a discoloration of the resulting recycled fiber caused by usingcolored PET in the recycling process.

The polymer PET containers used in the production of BCF may includeparticular percentages of clear and colored containers (e.g., by volume,by mass, etc.). For example, in particular embodiments, recycled BCF maybe produced using at least about 80% (e.g., 80%) clear containers and nomore than about 20% (e.g., 20%) colored containers. In variousembodiments, the colored containers that the system uses along withclear containers to produce the recycled BCF may include only recycledcontainers of a particular color (e.g., only green bottles, only bluebottles, only amber bottles, etc.). In various embodiments, the systemmay be configured to use containers of a particular shade of aparticular color. For example, the system may be configured to utilizelight blue containers (e.g., bottles of a particular light shade ofblue) but not to use dark blue containers. In still other embodiments,the system may be configured to use any suitable colored containers(e.g., or other sources of recycled PET) in any suitable ratio.

In various embodiments, the disclosed processes may utilize betweenabout 6.5 percent (e.g., 6.5 percent) and about nine percent (e.g., ninepercent) colored PET with the remainder being clear PET. In otherembodiments, the disclosed processes may use between about six and aboutten percent colored PET. In still other embodiments, the disclosedprocesses may use up to about ten percent colored PET with balancesubstantially clear PET. In still other embodiments, the disclosedprocesses may utilize between about one percent colored PET and aboutten percent colored PET with balance substantially clear PET. In otherembodiments, the disclosed processes may use any other suitable ratio ofcolored recycled PET to clear recycled PET.

In various embodiments, an amount of non-clear PET bottles used in thedisclosed processes may be based at least in part on a color of carpetinto which the BCF produced by the disclosed processes will ultimatelybe made. For example, for darker carpets, the BCF used in their creationmay be produced using a higher percentage of colored (e.g., non-clear)recycled PET polymer containers. In various embodiments, the use of ahigher percentage of colored PET containers may result in darker BCFfilament, which may, for example, be unsuitable for the production ofparticular colored carpets (e.g., lighter carpets). Carpets that willultimately be dyed in darker colors (e.g., or solution dyed into adarker color) may be more suitable for production using BCF produced atleast partially from colored PET containers. For example, the productionof BCF for use in brown carpets may utilize at least a particular amountof amber PET bottles in the recycling process (e.g., 20% amber and 80%clear, or any other suitable ratio).

In a particular example, the system may use 2% or less of non-clear PETbottles in the process when producing relatively light-colored BCF. Thismay help to reduce or eliminate the need to use offsetting colorconcentrate (as discussed in greater detail below) to achieve thedesired light-colored BCF.

In certain situations, it may be advantageous to use high percentages ofnon-clear PET containers since doing so may reduce the amount ofsolution dye needed to achieve the desired color. For example, it may beadvantageous to use over about 80%, over about 90%, over about 95%, orabout 100% non-clear PET in using the process to produce certaindark-colored (or other colored) recycled BCF. In various embodiments, itmay be advantageous to use over 95% non-clear PET in producingdark-green recycled BCF since doing so may reduce the amount of solutiondye needed to attain the desired dark-green color.

In various embodiments, it may be acceptable to use the percentages ofnon-clear PET that are commonly available in purchased lots of curbsiderecycled bottles. Such percentages typically range from between about6.5% to 9.5% non-clear PET. In particular situations, where such rangesare acceptable, the system may be adapted not to sort non-clear PET fromclear PET. Rather, non-clear and clear PET may be processed and usedtogether according to various embodiments. However, non-PET polymers maybe separated from the mix and discarded as described above.

In particular embodiments, the system may be configured to use anysuitable solution dyeing technique to at least partially offset (e.g.,substantially offset) any discoloration of the BCF filament resultingfrom the above process when utilizing colored recycled PET. In variousembodiments, the system may be configured to add a color concentrate topolymer flakes prior to extrusion (e.g., or to polymer melt during orafter extrusion) in order to at least partially offset a coloration ofthe resultant filament due to the use of colored recycled PET. Such acolor concentrate may include any suitable color concentrate, which may,for example, result in a particular color of polymer fiber (e.g., bulkedcontinuous filament) following extrusion. In various embodiments, addingcolor concentrate to the flakes prior to extrusion may result in polymerfilament that is at least partially impregnated (e.g., impregnated) witha color pigment. The impregnated color pigment may offset anydiscoloration of the resulting fiber that may have resulted due to theuse of colored recycled PET in the extrusion process. Carpet producedfrom solution dyed filament may be highly resistant to color lossthrough fading from sunlight, ozone, harsh cleaning agents such asbleach, or other factors.

In various embodiments, the color concentrate includes any suitabledispersion of color in a compatible carrier. In some embodiments, colorconcentrates are designed so that, when added to a natural resin (e.g.,PET) in a set proportion, they color the resin substantially evenly(e.g., evenly) to match a desired color. In some embodiments, the colormay comprise mixtures of pigments, which may, for example, includeparticles of insoluble colored material, in the resin. In otherembodiments, color concentrates may include one or more polymer-solubledyes that are suitable alone or in combination with one or morepigments.

In particular embodiments, the system is configured to add between abouttwo percent (e.g., two percent) and about three percent (e.g., threepercent) color concentrate by mass to the polymer flake. In otherembodiments, the system is configured to add between about zero percent(e.g., zero percent) and about three percent (e.g., three percent) colorconcentrate by mass or volume. In still other embodiments, the system isconfigured to add up to about six percent (e.g., six percent) colorconcentrate by mass to the polymer flake prior to extrusion. In someembodiments, the system is configured to add between about one percent(e.g., one percent) and about three percent (e.g., three percent) colorconcentrate by mass to the polymer flake. In still other embodiments,the system is configured to add any suitable ratio of color concentrateto polymer flake in order to achieve a particular color of moltenpolymer (and ultimately polymer fiber) following extrusion.

It should be understood that, in the various contemplated embodiments, acolor concentrate may be added during any suitable phase of theprocesses described in this document. For example, in variousembodiments, such as any of the examples discussed above, the system maybe configured to add the color concentrate following extrusion of thepolymer flake by a first single-screw extruder section but prior tofeeding the resultant polymer melt through an extruder's multiple screwsection, as discussed herein. In other embodiments, the system may add acolor concentrate after the flake has passed through an extruder'smultiple screw section but prior to passing the polymer melt through asecond single screw section, as discussed herein. In still otherembodiments, the system may add a color concentrate while the flakesand/or polymer melt are being extruded in a first single-screw extrudersection, into a multiple screw section, into a second single screwsection, into any combination of these, or at any other suitable phaseof the process. In still other embodiments, the system may add the colorconcentrate during one or more (e.g., a plurality) of the phases of theprocess described herein (e.g., the system may add some colorconcentrate to the polymer flake prior to passing the flake through asingle-screw extruder section and also add solution color concentratefollowing extrusion through a multiple screw section).

In various embodiments, the use of a color concentrate may at leastpartially mask any coloration of the resulting BCF created using thedisclosed processes using colored recycled PET. In such embodiments, theresulting BCF may have a color that is substantially similar to a colorof BCF produced using substantially only substantially clear (e.g.,clear) recycled PET and a color concentrate.

In various embodiments, the system may be configured to substantiallyautomatically adjust an amount of color concentrate added to the polymerflake and/or polymer melt in order to produce a desired color of BCFfilament, as discussed herein. In various other embodiments, the systemis configured to substantially automatically determine an amount ofcolor concentrate to add to the colored PET to sufficiently offset thecolor of the colored PET. In such embodiments, the system may, forexample, use a suitable feedback loop that includes: (1) determining acolor of bulked continuous filament produced by the process; (2)determining whether the color is acceptable (e.g., the color isdetermined to be a particular target color and/or the color isdetermined to meet one or more pre-determined color guidelines); and (3)substantially automatically adjusting an amount of color concentratebeing added to the colored PET upstream based at least in part on thedetermined color (whether the determined color is acceptable accordingto one or more pre-determined color guidelines). In particularembodiments, the system may be adapted to automatically adjust an amountof color concentrate being added to the colored (non-clear) PET toassure that it is sufficient for the resulting colored PET to satisfythe one or more pre-determined color guidelines.

In various embodiments, the process may utilize any suitable dyeingtechnique other than the solution dyeing technique described above to,for example, at least partially mask a coloration of the filamentproduced using the recycled BCF process described herein with coloredrecycled PET. For example, in various embodiments, the disclosedprocesses may utilize any suitable skein dyeing technique, any suitablecontinuous dyeing technique, any suitable space dyeing technique, anysuitable beck dyeing technique, or any other suitable dyeing techniqueor suitable combination of dyeing techniques.

In various embodiments, such as embodiments where the system adds one ormore solution dyes to recycled PET that includes colored PET, thedisclosed processes may include adding polytrimethylene terephthalate(PTT) (and/or any other suitable additive) to the PET prior to extrusionor melting, during extrusion or melting, along with the colorconcentrate, separately from the color concentrate, and/or at any othersuitable time. In various embodiments, the mixture of PTT (and/or otheradditive(s)) and PET may have an enhanced dyeability compared to PETthat has not been mixed with PTT. In particular embodiments, thedisclosed processes include using a mixture of between about fivepercent (e.g., five percent) and about fourteen percent (e.g., fourteenpercent) PTT (and/or other additive(s)) in the mixture by mass orvolume. In other embodiments, the disclosed processes include using amixture of between about six percent (e.g., six percent) and about tenpercent (e.g., ten percent) PTT (and/or other additive(s)) in themixture by mass or volume. In still other embodiments, the disclosedprocesses include adding up to about fourteen percent (e.g., fourteenpercent) PTT (and/or other additive(s)) by volume or mass (e.g., betweenabout zero percent and about fourteen percent PTT). In variousembodiments, the addition of PTT (and/or other additive(s)) to the PETmay reduce a cost of dyeing the resulting fiber.

In various embodiments, the disclosed processes may utilize virgin PTT.In still other embodiments, the disclosed processes may utilize recycledPTT. In some embodiments, PTT may be recycled from any suitable sourcesuch as, for example, recycled PTT carpet, recycled food containers,and/or other suitable PTT products. In various embodiments, the PTT mayinclude recycled PTT recovered (e.g., recycled) using the processesdescribed herein.

In various embodiments, the disclosed processes may be suitable forrecycling PTT for use in mixing the recycled PTT (or other suitableadditive) with PET to improve dyeability of the PET due to the similarchemical composition of PTT and PET. The resulting combination may havea higher durability and resilience than conventional polyesters (e.g.,PET). In particular embodiments, PTT may be particularly useful in theproduction of carpet due to PTT's stain-resistant qualities. PTT carpetsmay, for example, at least generally maintain their original appearancethrough simple vacuuming and hot water extraction. This may, forexample, result in a longer lifespan of carpet produced with PTT. Inparticular embodiments, PTT is substantially hydrophobic, which maycontribute to PTT carpet's stain resistance. In various embodiments, PTTcarpeting is also substantially soft (e.g., to the touch). PTT carpet'ssoftness may result from, for example, a lack of topically-appliedchemicals for stain protection due to PTT's inherent hydrophobictendencies. It should be understood, based on the above discussion, thatany suitable additive may be used in place of, or in addition to, PTT inthe examples discussed above.

In various embodiments, such as embodiments in which the system adds oneor more dye enhancers to recycled PET that includes non-clear PET, thedisclosed processes may include adding DEG (or any other suitable dyeenhancer) to the PET prior to extrusion, during extrusion, along withcolor concentrate, separately from color concentrate, or at any othersuitable time. In various embodiments, the mixture of the dye enhancerand PET may have an enhanced dyeability compared to PET that has notbeen mixed with the dye enhancer. In particular embodiments, the processincludes using a mixture of between about zero percent (e.g., zeropercent) and about five percent (e.g., five percent) dye enhancer (e.g.,DEG) in the mixture by mass or volume. In certain embodiments, theprocess includes using a mixture of between about one percent (e.g., onepercent) and about two percent (e.g., two percent) dye enhancer (e.g.,DEG) in the mixture by mass or volume.

Using Variable Quality Recycled PET Polymer Containers as SourceMaterial

The disclosed systems may be configured to adjust particular componentsof the process based at least in part on the source of recycled PETbeing used to produce the bulked continuous carpet filament. Forexample, because deposit PET bottles include fewer impurities that needto be removed during the initial cleaning and sorting phases of theprocess, the systems and methods set forth herein may be adjusted toprocess such bottles. In a particular embodiment, a pressure regulationsystem may be configured to maintain a pressure within an extruder ormelt processing unit chamber of between about 0 millibars and about 12millibars when flakes derived from deposit PET bottles are beingprocessed. Alternatively, PET flake derived from curbside recycled PETbottles may have greater quantities of impurities and other polymers.Thus, in such embodiments, a pressure regulation system may beconfigured to maintain a pressure within an extruder or melt processingunit chamber of between about 5 millibars and about 10 millibars toaddress such source material.

In various embodiments, the system may be configured to determine asuitable pressure at which to maintain the pressure within an extruderor melt processing unit chamber based at least in part on the source ofthe recycled PET. In other embodiments, the system is configured to omitone or more of the steps described herein or to include one or moreadditional steps to the steps described herein based at least in part onthe source of the recycled PET.

Alternative Sources of PET Polymer

The systems and processes described herein may be adapted for processingand preparing old carpet (or any other suitable post-consumer product)to produce new carpet yarn comprising 100% recycled carpet. In suchembodiments, the process may begin by grinding and washing recycledcarpet rather than recycled PET containers. In various embodiments whereold carpet is converted into new carpet yarn comprising 100% recycledcarpet, the process may include additional steps to remove additionalmaterials or impurities that may be present in recycled carpet that maynot be present in recycled PET bottles (e.g., carpet backing, adhesive,etc.). In various embodiments, the systems and processes describedherein may be adapted for processing recycled PET from any suitablesource (e.g., sources other than recycled bottles or carpet) to producenew carpet yarn comprising 100% recycled PET.

Conclusion

Many modifications and other embodiments of the invention will come tomind to one skilled in the art to which this invention pertains havingthe benefit of the teachings presented in the foregoing descriptions andthe associated drawings. For example, although the vacuum systemdiscussed above is described as being configured to maintain thepressure in the open chambers of the MRS extruder to about 1 mbar, inother embodiments, the vacuum system may be adapted to maintain thepressure in the open chambers of the MRS extruder or Multiple StreamSection at pressures greater than, or less than, 1 mbar. For example,the vacuum system may be adapted to maintain this pressure at betweenabout 0.5 mbar and about 12 mbar.

Similarly, although various embodiments of the systems described abovemay be adapted to produce carpet filament from substantially onlyrecycled PET (so the resulting carpet filament would comprise, consistof, and/or consist essentially of recycled PET), in other embodiments,the system may be adapted to produce carpet filament from a combinationof recycled PET and virgin PET. The resulting carpet filament may, forexample, comprise, consist of, and/or consist essentially of betweenabout 80% and about 100% recycled PET, and between about 0% and about20% virgin PET.

Furthermore, it should be understood that when ratios of polymers arediscussed herein (e.g., as a percentage) such as a ratio of coloredrecycled PET to clear recycled PET, color concentrate to polymer flake,etc., the percentages may include a percentage by volume, a percentageby mass, a percentage by weight, or any other suitable relative measure.

Also, while various embodiments are discussed above in regard toproducing carpet filament from PET, similar techniques may be used toproduce carpet filament from other polymers. Similarly, while variousembodiments are discussed above in regard to producing carpet filamentfrom PET, similar techniques may be used to produce other products fromPET or other polymers.

Furthermore, although various embodiments described herein are discussedas being adapted for producing carpet filament from polymer flakes, itshould be understood in light of this disclosure that the describedembodiments may, in various embodiments, be used to produce carpetfilament from any other suitable source of polymer.

In addition, it should be understood that various embodiments may omitany of the steps described above or add additional steps.

In light of the above, it is to be understood that the invention is notto be limited to the specific embodiments disclosed and thatmodifications and other embodiments are intended to be included withinthe scope of the appended claims. Although specific terms are employedherein, they are used in a generic and descriptive sense only and notfor the purposes of limitation.

We claim:
 1. A method for manufacturing pellets from polymer, the methodcomprising: melting a plurality of polymer flakes in a first section ofa melt processing unit to create a first single stream of polymer melt;separating the first single stream of polymer melt into multiple streamsof polymer melt by means of a separation element; passing the multiplestreams of polymer melt through a multiple stream section of said meltprocessing unit and into a receiving section of the melt processingunit, and exposing the multiple streams of polymer melt to a pressurewithin the multiple stream section of the melt processing unit as themultiple streams of polymer melt pass through the multiple streamsection of the melt processing unit, wherein a chamber pressure ismaintained within the multiple stream section of the melt processingunit as the multiple streams of polymer pass through the multiple streamsection, wherein the receiving section of the melt processing unitrecombines the multiple streams of polymer melt into at least onecombined stream of polymer melt; cooling the polymer melt and formingsaid pellets from the at least one combined stream of polymer melt; andwherein the intrinsic viscosity of the at least one combined stream isdetermined, and, in response to determining the intrinsic viscosity ofthe at least one combined stream of polymer melt, the chamber pressurewithin the multiple stream section of the melt processing unit isadjusted.
 2. The method of claim 1, wherein the method further comprisescrystallizing the plurality of polymer flakes, prior to melting theplurality of polymer flakes in the melt processing unit.
 3. The methodof claim 1, wherein the multiple streams of polymer melt fall into saidreceiving section of the melt processing unit under the weight ofgravity.
 4. The method of claim 1, wherein the receiving section of themelt processing unit comprises a particular extruder that recombinesrecombine the multiple streams of polymer melt into the at least onecombined stream of polymer melt.
 5. The method of claim 4, wherein theparticular extruder is disposed vertically below the separation element.6. The method of claim 1, wherein the separation element is adapted todivide the first single stream of polymer melt into at least 8 streamsof polymer melt.
 7. The method of claim 1, wherein the separationelement is an extrusion die defining a plurality of holes, each of theholes creating a respective one of the multiple streams of polymer melt.8. The method of claim 1, wherein the first section of the meltprocessing unit comprises a single screw extruder; and the receivingsection of the melt processing unit comprises a single screw extruder.9. The method of claim 1, wherein the plurality of polymer flakes isderived, at least in part, from polyethylene terephthalate (PET) flakesthat are derived from recycled PET bottles.
 10. A system formanufacturing pellets from polymer, the system comprising: means formelting a plurality of polymer flakes to create a first stream ofpolymer melt; means for routing the first stream of polymer melt througha separation element to generate multiple streams of polymer melt; meansfor exposing the multiple streams of polymer melt to a pressure within amultiple stream section of a melt processing unit; means for reducingthe pressure of the multiple stream section of the melt processing unitto a chamber pressure; means for, while maintaining the pressure of themultiple stream section of the melt processing unit at the chamberpressure, allowing the multiple streams of polymer melt to pass throughthe multiple stream section of the melt processing unit into a receivingsection of the melt processing unit; means for recombining the multiplestreams of polymer melt into at least one stream of polymer melt at thereceiving section of the melt processing unit; means for cooling said atleast one stream of polymer from the at least one stream of polymermelt; means for forming pellets from said at least one stream ofpolymer; wherein the system further comprises an intrinsic viscositymanagement system configured to determine an intrinsic viscosity of theat least one stream of polymer melt, and, in response to determining theintrinsic viscosity of the at least one stream of polymer melt, adjustthe pressure within the multiple stream section of the melt processingunit.
 11. The system of claim 10, wherein allowing the multiple streamsof polymer melt to pass through the multiple stream section of the meltprocessing unit into a receiving section of the melt processing unitcomprises allowing the multiple streams of polymer melt to fall throughthe multiple stream section of the melt processing unit under the weightof gravity.
 12. A system for manufacturing pellets from polymer, thesystem comprising: a first section of a melt processing unit, the firstsection being configured to melt polymer to create a first single streamof polymer melt; a separation element configured to receive the firstsingle stream of polymer melt and divide the first single stream ofpolymer melt into multiple streams of polymer melt; a multiple streamsection of the melt processing unit configured to: receive the multiplestreams of polymer melt, allow the multiple streams of polymer melt topass through the multiple stream section and into a receiving section ofthe melt processing unit, and expose the multiple streams of polymermelt to a pressure within the multiple stream section of the meltprocessing unit as the multiple streams of polymer melt pass through themultiple stream section of the melt processing unit; and a pressureregulation system configured to maintain the pressure within themultiple stream section of the melt processing unit at a chamberpressure as the multiple streams of polymer pass through the multiplestream section, wherein: the receiving section of the melt processingunit is configured to: receive the multiple streams of polymer melt,recombine the multiple streams of polymer melt into at least onecombined stream of polymer melt, and convey the at least one combinedstream of polymer melt toward means for cooling and forming said atleast one combined stream of polymer melt into said pellets, wherein thesystem further comprises an intrinsic viscosity management systemconfigured to determine an intrinsic viscosity of the at least onecombined stream of polymer melt, and, in response to determining theintrinsic viscosity of the at least one combined stream of polymer melt,instructing the pressure regulation system to adjust the chamberpressure within the multiple stream section of the melt processing unit.13. The system of claim 12, wherein: the first section is configured tomelt a plurality of polymer flakes to create the first single stream ofpolymer melt; the system further comprises a crystallizer configured toperform a crystallization step on the plurality of polymer flakes priorto melting the plurality of polymer flakes in the first section of themelt processing unit; and the multiple stream section of the meltprocessing unit is configured to allow the multiple streams of polymermelt to fall into a receiving section of the melt processing unit underthe weight of gravity.
 14. The system of claim 12, wherein the receivingsection of the melt processing unit comprises a particular extruder thatis adapted to recombine the multiple streams of polymer melt into the atleast one combined stream of polymer melt.
 15. The system of claim 14,wherein the particular extruder is disposed vertically below theseparation element.
 16. The system of claim 12, wherein the separationelement is adapted to divide the first single stream of polymer meltinto at least 8 streams of polymer melt.
 17. The system of claim 12,wherein the separation element is an extrusion die defining a pluralityof holes, each of the holes creating a respective one of the multiplestreams of polymer melt.
 18. The system of claim 12, wherein the firstsection of the melt processing unit comprises a single screw extruder;and the receiving section of the melt processing unit comprises a singlescrew extruder.
 19. The system of claim 12, wherein: the first sectionof the melt processing unit is a first extrusion means; the separationelement is a polymer melt separation means; the multiple stream sectionof the melt processing unit is a second extrusion means; the pressureregulation system is a pressure regulation means; and the receivingsection of the melt processing unit is a third extrusion means.